de Gallaí was born into a family of seven by his father Gerry of Belfast and his mother Nellie of County Donegal.
[1] In early 1994, de Gallaí received a call to audition for Riverdance's Eurovision Song Contest interval act.
Around that time, de Gallaí and long-time friend Joanne Doyle set up their own dance company called Dualta.
[2] 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.
On the back of this run, the show was nominated for two Drama Desk awards, "Outstanding Choreography" and "Unique Theatrical Event".