Tommy Smith was born in Liverpool, on 5 April 1945; he was an only child. His father died of pneumonia in 1959. Brought up a Catholic, he stopped attending church after witnessing the local priest stagger out of the house drunk after he came to the family home to offer his condolences. Smith joined the groundstaff at Anfield the following year, becoming a schoolboy associate of Liverpool, the club he had supported all his life. Initially a , he impressed manager Bill Shankly enough to bypass two of the club's four reserve teams to immediately play for the 'A' team. He further made an impression in the 1961–62 pre-season when he beat imposing centre-half Ron Yeats to a header to score in training. He turned professional in the summer of 1962, on wages of £18-a-week.
He made his first debut for the "Reds" on 8 May 1963, replacing an injured Jimmy Melia, in a 5–1 home victory over Birmingham City. However he made no further appearances throughout the rest of the 1962–63 season, and did not feature in the 1963–64 title winning season. He married Susanne in July 1964, following a four-year courtship.
He scored his first goal for Liverpool in his second match, playing at inside-left in a 3–2 defeat to Blackburn Rovers at Ewood Park on 29 August 1964. He kept his place for the following game, and again scored as Liverpool beat Leeds United 2–1. He was returned to the reserves after two more appearances, before returning to the first team as a defender in a 3–0 win over Belgian side Anderlecht in the European Cup; after the match Shankly said that "The game marked out Tommy Smith as a fine player. The boy has arrived". He ended the 1964–65 season with four goals in 25 league games, spent mostly at right-half. He also played in every game of Liverpool's FA Cup run as they beat West Bromwich Albion, Stockport County (after a replay), Bolton Wanderers, Leicester City (after a replay), and Chelsea to reach the 1965 FA Cup Final against Leeds United at Wembley Stadium; Liverpool won the game 2–1 to lift the trophy for the first time in the club's history.
He played in the 1965 FA Charity Shield against Manchester United at Old Trafford, where a 2–2 draw meant that two clubs shared the trophy. Liverpool then recovered from a loss and a defeat to Sheffield United in the opening two games of the 1965–66 season to go on a strong run of form that included convincing victories over West Ham United (5–1), Merseyside derby rivals Everton (5–0), Nottingham Forest (4–0), Northampton Town (5–0), and Blackburn Rovers (5–2); Smith managed to score against both Everton and Blackburn. They went unbeaten for a total of 18 games from October to late February, and then lost just one of their final ten games to secure the league title with a six-point lead over runners-up Leeds United. They had conceded just 34 goals, the lowest total of any team in . Liverpool also reached the 1966 European Cup Winners' Cup Final to face German side Borussia Dortmund at Hampden Park, but Smith admitted that his side "lacked our usual edge and appeared disjointed" as they lost the game 2–1 in extra-time.
Smith played in the 1966 FA Charity Shield against Everton at Goodison Park, helping his side to a clean sheet and a 1–0 victory. This would prove to be the last trophy for five years however, despite a good start to the 1966–67 season that included a 5–0 win over Leeds United. Their form slipped in the second half of the campaign, as they fell to fifth place. Liverpool were more consistent across the 1967–68 campaign, but ended up in third-place, three points behind champions Manchester City. They came even closer in the 1968–69 season, where a 0–0 draw with Leeds at Anfield was enough to win Leeds the title, whilst Liverpool went on to finish as runners-up.
Smith was given the honour of club and led the team to the 1971 FA Cup final, which Liverpool lost to Arsenal 2–1 after extra time. In 1972–73, Smith skippered the team to their first double success of the League and UEFA Cup, when they topped the league by three points over Arsenal and beat Borussia Mönchengladbach in the UEFA Cup final 3–2 on aggregate.
The following season, after Smith complained to Shankly at being left out of the team for a game, he had the big disappointment of losing the captaincy to Emlyn Hughes. Earlier, Hughes had told Shankly to remove the captaincy from Smith and give it to a younger man. When he returned, he was also moved from his favoured central defensive role to full back. Although Smith ultimately settled his differences with Shankly satisfactorily, a long-running feud developed between Smith and Hughes which led to some tension in the Liverpool dressing room, where the older players remained loyal to Smith and voiced their dislike of Hughes's chattiness (and parsimony in the pub).
Hughes went on to lift the FA Cup as captain in 1974 after Liverpool comprehensively beat Newcastle United 3–0 in one of the most one-sided of Wembley finals. Having lost the captaincy Smith missed out on receiving the trophy from Princess Anne, he did have the pleasure of setting up the third and final goal for the young striker Kevin Keegan, a stunning team goal.
As Smith's twilight years approached, he made fewer appearances and with the emergence of youngsters Phil Thompson and Phil Neal as central defender and full back respectively, though he still played an important role as Liverpool managed another League and UEFA Cup dual success in 1976, when he appeared 24 times in the league and played a left-back role in both legs of the UEFA final. Smith spent the close season in the summer of 1976 in the United States, playing 17 games on loan as a defender for the Tampa Bay Rowdies, where he continued his trademark toughness and earned the nickname, "The Tank".
Back in Liverpool, Smith was left out of the side that started the 1976–77 season but, when Thompson picked up an injury in Liverpool's 1–0 win over Newcastle in the month of March, he was recalled and kept his place as the side went on to retain the League title. Smith then played in the 1977 FA Cup Final which Liverpool lost to bitter rivals Manchester United, thereby losing the chance of a treble, with the club's first European Cup final in Rome due a few days later. Despite the disappointment of the defeat at Wembley, Liverpool played magnificently to beat old UEFA Cup foes Borussia Mönchengladbach 3–1, with Smith scoring a towering second-half header from a corner taken by Steve Heighway to make the score 2–1. It was his first goal of the season, and the 48th and final for the club. The BBC commentator Barry Davies described the goal with the words "It's Tommy Smith! Oh what an end to a career."
Smith decided to delay his retirement and played a further season for Liverpool but missed the successful retention of the European Cup after he dropped a pick-axe on his foot, breaking his toe. He picked up a runners-up medal in Liverpool's first ever after they lost a replay to Nottingham Forest.
He spent the summer of 1978 in the NASL with the Los Angeles Aztecs. He started as a player but became player/head coach halfway through the season. At the end of the season he was replaced by Dutch legend Rinus Michels.
Smith left for Swansea City after 638 games in 1978, receiving the M.B.E for services to football that same year. The Swans were being managed by his former Liverpool teammate John Toshack at the time and Smith helped Swansea to promotion from the old Third Division. He retired from playing in 1979.