In early 1994, de Gallaí received a call to audition for "Riverdance's" Eurovision Song Contest interval act. It was here that he met Michael Flatley, and after just two weeks of rehearsals, he was picked as one of just 24 dancers for the performance. Around that time, de Gallaí and long-time friend Joanne Doyle set up their own dance company called "Dualta". He and Joanne both went on to be part of the "Riverdance: The Show" premiere in Dublin in February 1995, and both later starred for "Riverdance" as lead dancers for the Liffey Company. de Gallaí's tenure with "Riverdance" spanned 9½ years, with his final gig for the show coming in 2003 at the Opening Ceremony of the Special Olympics at Croke Park, Dublin. As the lead male dancer for seven of those years, he performed in Europe, Asia, Australia and New Zealand, and performed live for Presidents McAleese and Robinson of Ireland, Queen Elizabeth, and Prince Charles. He was also honoured to perform for and to meet King Hussein of Jordan, the Emperor of Japan, the Crown Prince of Japan, Princess Diana, Prince Rainier of Monaco, and Queen Sonia of Norway. de Gallaí continued on with "Riverdance" as a dance director and later helped out behind the scenes with the 2010 DVD, "Riverdance: Live from Beijing".