Laine did not take up singing professionally until her mid-twenties. Her early influences as a singer were Ella Fitzgerald, Sarah Vaughan, Judy Garland and Lena Horne. She auditioned successfully, at the age of 24, for John Dankworth's small group, the Dankworth Seven, and later his orchestra, with which she performed until 1958. Dankworth and Laine married that year in secret at Hampstead Register Office. The only witnesses were the couple's friend, pianist Ken Moule, and Dankworth's arranger, David Lindup. The couple had two children, who are both successful musicians in their own right: Alec who lives in the US, and Jacqui, a British singer who has released a number of albums.