Robbie Kay was born on 13 September 1995, making him 28 years old as of now. Kay's family relocated to the Czech Republic, where he discovered a notice on a school board seeking English-speaking children to be extras in a film. Despite having no prior acting experience, this opportunity led to him securing a speaking role in The Illusionist, although his scenes were ultimately cut from the final film.
Following small roles in Hannibal Rising and My Boy Jack, the Canadian production company behind Fugitive Pieces invited him to audition for the role of young Jakob, which involved a nine-week shooting schedule, three of which were spent on Greek islands. The team behind Fugitive Pieces auditioned over 150 boys before selecting 10-year-old Robbie, who had been living in Prague for two years. He then dedicated a year to studying acting, singing, and dancing at one of Britain's Stagecoach theatre schools.
Kay appeared in the 2008 miniseries Pinocchio, playing the title character. After Pinocchio, he portrayed Sam, a boy diagnosed with leukaemia, in Ways to Live Forever, which screened in late 2010. He also featured in Pirates of the Caribbean: On Stranger Tides as the Cabin Boy and more recently played Peter Pan in Once Upon a Time. In March 2015, Kay was cast as a high school student named Tommy Clark in the TV series Heroes Reborn.