Laird Mackintosh made his Broadway debut in 2011 in the role of George Banks in Mary Poppins at the New Amsterdam Theater in New York City. In 2013 he played John Utterson in the Broadway production of Wildhorn's Jekyll and Hyde. Mackintosh began his career as a dancer in the National Ballet of Canada (1990-1992).
In 1993 he joined the Toronto (LivEnt) production of Andrew Lloyd Webber's The Phantom of the Opera in the role of Porter/Marksman and subsequently went on to play the leading role of Raoul for three years and also to understudy the role of the Phantom. He performed with Toronto's Opera Atelier between 1997 and 2002. In 2002, Mackintosh joined the company of the Stratford Shakespeare Festival appearing as Freddy Eynesford-Hill in My Fair Lady. He remained with the company for eight seasons, playing many leading roles. He has also played Robert in The Drowsy Chaperone (Vancouver), Phil Davis in White Christmas (Halifax), Prince Charming in Ross Petty's Cinderella (Toronto), Gustl in The Land of Smiles and Algernon Moncrieff in Earnest, the Importance of Being (Toronto Operetta Theatre).
On August 26, 2013, Mackintosh joined the Broadway cast of The Phantom of the Opera as Monsieur Andre and understudy for the Phantom. In December of 2019, he joined the U.S. tour of My Fair Lady in the role of Henry Higgins.