Brøndby IF was founded in 1964 as an amateur club in the 6th tier of the 11 Danish leagues, the Serie 1, where they finished their two first seasons in fourth place. Among the players of the early years was team captain Per Bjerregaard, a doctor who had moved to Copenhagen from Jutland, and Hans Gregersen, who was the mascot of the team until his death by syphilis in 1967. In 1967, the club hired coach Leif Andersen who instantly secured promotion to Sjællandsserien (the Zealand series). After a few mediocre years, a new coach, John Sinding, was brought in, and the club won promotion to Danmarksserien (the Denmark series).
In 1973, Per Bjerregaard stopped his active career at 27 years of age and became chairman of Brøndby; his first action was to sack head coach Sinding. In his place, Brøndby hired former professional and player Finn Laudrup, who took over as head coach while he still took actively part in the matches as a player. Laudrup joined his brother-in-law Ebbe Skovdahl in the Brøndby team, and he brought his two young sons Brian and Michael Laudrup with him to the club. Under Finn Laudrup's influence, the club's playing style was changed to a more attacking strategy, even though Laudrup decided to fully concentrate his efforts as a player after only a year. After winning promotion in 1974, Laudrup left Brøndby in the 3rd Division in 1976 to play for KB in the Danish top-flight league (then named the 1st Division) and a year later Michael Laudrup, the brightest talent in Danish football, followed.
In 1977, Brøndby moved up into the 2nd Division, and were one of the clubs who quickly adapted to the new times of paid football in the best Danish leagues in 1978. Per Bjerregaard persuaded Finn Laudrup into returning to Brøndby in 1981 on a professional contract, and following a season of 85 goals in 30 matches, Brøndby won promotion to the top-flight 1st Division under coach Tom Køhlert. Finn Laudrup subsequently ended his career at age 36, but in his place Michael Laudrup returned for the
1982 season, being one of ten players leaving KB that year.
Brøndby won their 1st Division debut match 7–1 over fellow promoted team B 1909 in a match which featured two goals from Michael Laudrup. He was subsequently called up for the Denmark national team, and on 15 June 1982 he became the first Brøndby player to win a for the national team. Brøndby finished their first 1st Division season in fourth place with Laudrup the league's third top goal scorer with 15 goals, earning him the Danish Player of the Year award. In 1983, Laudrup was sold to Juventus in the then-biggest transfer deal in Denmark, giving Brøndby the economic foundation to expand further.
After four years in the top division, Brøndby won their first Danish championship in 1985 and played its first European match when the club beat Hungarian champions Budapest Honvéd 4–1 in the 1986 European Cup. In 1986, Brøndby became the first Danish club of fully professionals when ten players were signed full-time, and the club was introduced at the Copenhagen Stock Exchange in 1987.
European success (1987–1992)
Throughout the second half of the 1980s, the team dominated the league and did not finish lower than second place until 1992. The team was built around talented Danish players, and from 1987 to 1991 players from Brøndby won the Danish Player of the Year award every year. The recipients formed the backbone of the Denmark national team which later won UEFA Euro 1992, and was the first goalscorer in the 2–0 Euro 1992 final win John "Faxe" Jensen (1987), national team captain Lars Olsen (1988), the World's Best 1992 and 1993 award winner Peter Schmeichel (1989), four-time Danish Player of the Year award winner Brian Laudrup (1990) and the second goalscorer of the Euro 1992 final Kim Vilfort (1991). The club became used to winning the national title and turned its attention towards European success.
In 1990, Brøndby hired former national team captain Morten Olsen as coach, and under his reign, the 1990–91 UEFA Cup became the high point in the short history of the club. Especially the meriting wins over German sides Eintracht Frankfurt and Bayer Leverkusen, and Russian club Torpedo Moscow saw the many Danish profiles shine, and the club was minutes from qualifying for the final match of the tournament. In the 88th minute of the semi-final, however, a Rudi Völler goal denied Brøndby a trip to the UEFA Cup final in favour of Roma. Following the impressive European display by the comparatively small club, important members of the team, including Lars Olsen, top scoring Bent "Turbo" Christensen and star goalkeeper Peter Schmeichel, left the club.
The following year, 1992, was the worst year in the club's history as the intended takeover of the Danish bank Interbank went awry. It was expected that European Cup success would boost the Brøndby stock value in order to finance the buy, but as the club was beaten by Dynamo Kyiv in the 1991–92 European Cup qualification, the stocks never reached the value necessary to finalize the deal. It had been arranged for financial backers Hafnia Insurance Company to step in and take over the buy in case Brøndby could not finance it, but as Hafnia went bankrupt, Brøndby were forced to buy Interbank and financial collapse was imminent as club debts amassed to 400 million DKK. A long-term rescue plan was initiated to save the club, but these events influenced the performance of the team and the championship, now called the Danish Superliga, was not won again until 1996.
The rebuilding of the team was led by head coach Ebbe Skovdahl, who deployed the team in a . The return to the club of Euro 1992 veterans John Jensen and captain Lars Olsen combined with the emergence of goalkeeper Mogens Krogh and striker Ebbe Sand got the club back on its feet. The rebuilding culminated in the 1995–96 UEFA Cup elimination of Liverpool, though Roma once again knocked Brøndby out. Including that year, Brøndby won three Danish championships in a row, and the next year's UEFA Cup saw one of the biggest upsets in Brøndby history, as a 3–1 home defeat to Karlsruher SC was changed to an aggregate win when Brøndby beat the team of Euro 1996 winner Thomas Häßler 5–0 away in Germany. Most importantly for the club's economy, Brøndby qualified for the new format of the European Cup, rebranded as the UEFA Champions League. The Champions League qualification meant six guaranteed matches in a group stage with three of the biggest teams of Europe, and when they were paired with Barcelona and later finalists Manchester United and Bayern Munich, Brøndby faced very economically attractive matches. Despite winning 2–1 over Bayern in the first match of the group stage, Brøndby conceded 18 goals in 6 matches and were eliminated with a single win to their name.
Skovdahl decided to take a stab at coaching at Scottish club Aberdeen and Brøndby took a more Scandinavian approach, in search of stable success in the European competitions with Norwegian club Rosenborg the role model. The club hired Norwegian manager Åge Hareide in 2000, who proclaimed a shift in line-up to a more attacking . With Hareide came a handful of Scandinavian players of whom especially player Mattias Jonson became a fan favourite.
The year 2000 was also the year the club finalized a planned expansion of Brøndby Stadium from a 20,000 to a 29,000 capacity, making it the second largest stadium in Denmark, only trailing the Parken Stadium of F.C. Copenhagen. At the cost of 250 million DKK, the vast expenditure was seen as a sign that the club was out of its former financial crisis. The building project was finalized in Autumn 2000, and on 22 October, 28,416 spectators saw Brøndby beat Akademisk Boldklub 4–2 in the opening match of the rebuilt stadium.
Hareide's visions of a 4–3–3 system never worked out, and the team soon returned to the well-known 4–4–2 setup. As he slowly lost hold of a ten-point lead to rivals F.C. Copenhagen, gained in a great first half of the 2001–02 Superliga season, Hareide took his leave in spring 2002 before the last matches of the season. He was replaced by youth team coach Tom Køhlert, who, though reluctant to take the job, gave first team debuts to the top youth team players, most notably Thomas Kahlenberg, who helped the club narrowly secure the championship win on goal difference.
The Laudrup years (2002–2006)
In the 2002–03 pre-season, Brøndby announced that Danish icon Michael Laudrup was taking the manager seat in his old club with John Jensen, also a club legend, as his assistant. In their first season, there were massive cuts from the very large squad; ten players were put in the reserves squad or sold and a talent squad was established. The club was to rely even more home grown players as Brøndby was already famous for developing very talented players. In the process, Laudrup told several players to find new clubs as he thought they would not fit in the playing style he wanted to implement.
During the Laudrup era, Brøndby won the in 2005, the latest championship the club has won. The club was relatively successful in the European competitions as Schalke 04 was beaten 2–1 in the 2003–04 UEFA Cup but was later beaten by Laudrup's former club Barcelona, 0–1.
In May 2006 it was announced that Laudrup and Jensen could not agree with the board of Brøndby regarding an extension of their contracts, and the duo left the club.
Years of crisis (2006–2013)
The two were replaced by Dutch coach René Meulensteen, who had a rough start in charge of the first team. Together with newly appointed Anders Bjerregaard – son of director Per Bjerregaard – Meulensteen bought a number of questionable players in the final days of the summer transfer window. In the first matches, the new coach struggled with injuries among the key players and the team had problems living up to the expectations.
Meulensteen resigned after six months, leaving Brøndby in seventh position halfway through the 2006–07 Superliga. The official explanation for his departure was that his family could not settle in Denmark, but soon after, the former coach revealed major infrastructural problems in the club's organization, calling the club "a very sick patient requiring immediate attention", as well as cliques inside the first team. In order to solve the clique problems, he had gone to director Per Bjerregaard to fire three key players – Marcus Lantz, Thomas Rytter and one club man Per Nielsen – in order to reestablish the balance in the first team squad, a demand Danish football experts later described as the quickest way of getting sacked.
Tom Køhlert took the managerial reins once more, this time as a permanent solution on a two-and-a-half-year contract.
After losing 2–4 to Horsens on 26 August, their 23rd consecutive away match without a victory, the team was greeted by approximately 200 furious fans and cries like "die mercenaries" and "we are Brøndby, who are you?" on their return to Brøndby.
On 31 August 2007, Per Bjerregaard announced that he resigned from the director seat, and instead took over as chairman of the board in Brøndby IF. Shortly after his resignation, Peter Schmeichel announced that he was ready to purchase Brøndby and become a director. The announcement divided the fans. Some praised the former player for trying to save the club, while others criticized him for bringing investor Aldo Petersen along, a keen supporter and former stockholder of rivals F.C. Copenhagen. Schmeihel's offer, however, was rejected. On 1 April 2008, Hermann Haraldsson was appointed to the vacant position.
Following a disappointing beginning of the 2007–08 Superliga season with only five points gained from seven matches, manager Tom Køhlert made it clear in August 2007 that the Danish Cup now had a higher priority for the club. The change of priorities was successful, and Brøndby won their first domestic title in almost three years on 1 May 2008 when Esbjerg were defeated 3–2 in the final of the 2007–08 Danish Cup.
Soon after, manager Køhlert declared his job complete, prompting club chairman Bjerregaard to search for his replacement. On 16 June 2008, the club announced the appointment of former player and head coach of Horsens, Kent Nielsen. Nielsen took charge of the first team on 1 January 2009. Former legendary coach Køhlert led Brøndby to the first place, where they stayed until Nielsen arrived.
On 1 July 2008, KasiGroup replaced Codan as the main sponsor of the club. The partnership involved a cooperation with UNICEF, making Brøndby the third club in Europe next to Barcelona and Swedish side Hammarby Fotboll to wear the UNICEF logo on their shirts. Furthermore, KasiGroup entered a sponsorship for the stadium and promised substantial funds for taking the player squad to the next level. During the 2008 summer break, this contributed to Brøndby transferring five new players with national team experience in order to strengthen the team.
On 30 December 2009, KasiGroup owner Jesper Nielsen got in trouble with Brøndby and refused to pay the remainder of the money. On 31 August 2012, Brøndby told the Danish media B.T. that KasiGroup now owes the club more than 45 million DKK (€6,000,000 / £5,000,000). The two will meet in court next year. Nielsen told B.T. that he could recognize the amount but that his lawyer thought they could make a settlement at a much lower figure than the 45 million.
Nielsen was the owner of AG København, which went bankrupt on 31 July 2012 due to his overuse of money. Nielsen is thus both chased by Brøndby and the Danish tax authorities. Brøndby is still looking for a new main sponsor as it has not been possible to find one yet. Brøndby started looking for a new sponsor in 2010 when they realized that KasiGroup did not intend to pay the amount stipulated by contract.
Resurgence, and return to success (2013–)
In May 2013, the club was again close to bankruptcy, but was taken over and saved by a small group of investors led by Ole Abildgaard and Aldo Pedersen. On 10 April 2014, the new main investor, Jan Bech Andersen, took over as chairman and replaced the board with his own team. On 14 July 2014, the club announced they had signed a one-year contract with Danish betting company Bet25 as their main sponsor, with the option to extend the contract for an additional two years. The deal was said to be worth "a significant amount in the million Danish kroner range". The deal includes a strategic partnership between Brøndby and Bet25. As part of the contract, Danish telecommunications company TDC A/S (which owns 51% of Bet25), installed wi-fi in Brøndby Stadium in December 2014. On 15 January 2015, it was announced Brøndby and Bet25 extended their contract until summer 2017.
In 2016, announced his resignation as Brøndby IF manager after chairman Jan Bech Andersen had discredited him on an online chat-forum under the name of "Oscar", the case being referred to as "Oscar-gate" by the media. Bech Andersen stepped down as chairman after the incident but continued as board member.
On 17 May 2016, Brøndby named Alexander Zorniger as their new manager. His first two seasons as manager resulted in two second-place league finishes and a Danish Cup win. On 18 February 2019, Zorniger was sacked as manager of the club, following a string of bad results. Martin Retov and Matthias Jaissle, former assistants under Zorniger, were appointed as caretaker managers the next day.