Denny Doherty was born in Halifax, Nova Scotia, the youngest of five kids. He grew up in Halifax's north end in a staunch Catholic household. His father was a dockworker and he described his mother as a "housewife and mystic". He and three friends, Richard Sheehan, Eddie Thibodeau and Mike O'Connell, began their musical career in 1956 with a band called the Hepsters. Two years later, they disbanded. In 1960, still in Halifax, Doherty, aged 19, along with Pat LaCroix and
Richard Byrne, began a folk group, The Colonials.
Columbia Records signed the group several months later, upon which time they changed their name to The Halifax III. The band recorded two LPs and had a minor hit, "The Man Who Wouldn't Sing Along With Mitch", but broke up in 1963 in Los Angeles.
In 1963, Doherty established a friendship with Cass Elliot when she was with a band called "The Big 3". While on tour with "The Halifax III", Doherty met John Phillips and his new wife, model Michelle Gilliam.
A few months later, The Halifax III dissolved, and Doherty and their accompanist, Zal Yanovsky, were left broke in Hollywood. Elliot convinced her manager to hire them. Thus, Doherty and Yanovsky joined the Big 3 (increasing the number of band members to four). Soon, after adding even more band members, they changed their name to the "Mugwumps"who soon broke up also due to insolvency after which Yanovsky went on to form The Lovin' Spoonful with John Sebastian.
About this time, Phillips' new band, "The New Journeymen", needed a replacement for tenor Marshall Brickman, who had left the folk trio to pursue a career in television writing, and the group needed a quick replacement for their remaining tour dates. Doherty, then unemployed, filled the opening. After the New Journeymen called it quits as a band in early 1965, Elliot was invited into the formation of a new band, which became "The Magic Cyrcle". Six months later in September 1965, the group signed a recording contract with Dunhill Records. Changing their name to The Mamas & the Papas, the band soon began to record their debut album, If You Can Believe Your Eyes and Ears. The Mamas & the Papas song "Creeque Alley" briefly outlines this history.