Due to his diminutive size, he has appeared in a number of similar-sized roles, such as the Oompa-Loompas in Charlie and the Chocolate Factory, Keenser in Star Trek, and in television series such as The X-Files and Eastbound & Down. Roy made his professional screen acting debut in a 1976 episode of The New Avengers entitled "Target!" as a character named Klokoe. He would later make his film debut that same year, in The Pink Panther Strikes Again, as the Italian Assassin.
Another early role was as Mr.
Sin, the "pig-brained Peking Homonculus", a villain with a distinct appetite for homicide, in the Doctor Who serial The Talons of Weng-Chiang. In 1979, Roy also played a genetically engineered life form "Decima" in the first season Blake"s 7 episode "The Web" as well as the diminutive chess genius, "The Klute", in the second season Blake"s 7 episode "Gambit".
He has played apes in two movies: Greystoke - The Legend of Tarzan, Lord of the Apes and again in the Tim Burton remake of Planet of the Apes (2001) in two roles: one as a young gorilla boy and as Thade"s niece. He has worked for Burton in three other films, Big Fish (2003), Charlie and the Chocolate Factory (2005) and Corpse Bride (also 2005) where he supplied General Bonesapart"s voice.
He played all the Oompa-Loompas (165 of them) in Charlie and the Chocolate Factory.
He appeared in Transformers: Revenge of the Fallen (2009) as an Egyptian border guard and in the film Star Trek (also 2009) as Keenser, Montgomery Scott"s assistant on the ice planet Delta Vega. Roy played a green man while doing a commercial shoot for Ozocleanse. In one of his more prominent speaking roles, Roy played Aaron, a violent Mumbai-born Mexican criminal, in second season of the Home Box Office comedy, Eastbound & Down.
Deep starred as Sandeep Majumdar in the 2012 short film The Ballad of Sandeep.