[4] His voice acting roles included Claude Frollo in Disney's The Hunchback of Notre Dame (1996),[4] Megabyte in ReBoot (1994–2001), Shere Khan in The Jungle Book 2 (replacing George Sanders, who played the character in the original film), the TV series TaleSpin, and the Elder God (plus various other roles) in the Legacy of Kain series of video games.

[3] Jay also made many distinguished on-screen appearances, including the role of Nigel St John on Lois and Clark: The New Adventures of Superman (1993–1995).

[9] Within three months of relocating to South Africa at the age of 33,[8][10] Jay found himself acting in radio dramas such as the detective series Sounds of Darkness where he played a savvy but blind FBI agent (1967–1972).

[13] To bridge the gap between the visual orientation of the British television series and the sound-only perspective of radio, Jay created a narrator which he embued with irony and scepticism.

[12] For the BBC series Fall of Eagles (1974) he portrayed Tsar Alexander III of Russia, during which time he met Patrick Stewart, who played Vladimir Lenin.

Bigger roles included Paracelsus on the 1987 CBS TV series adaptation of Beauty and the Beast; Minister Campio on Star Trek: The Next Generation (1992); and Lex Luthor's villainous aide-de-camp Nigel St. John in Lois & Clark: The New Adventures of Superman (1993–95).

[7] Jay's voice-over work included Monsieur D'Arque, the amoral asylum superintendent, in Disney's 1991 hit animated film version of Beauty and the Beast.

According to one source,[26] Jay was preferred to Patrick Stewart, Derek Jacobi and Ian McKellen for the voice of the main antagonist Judge Claude Frollo in Disney's 1996 animated film adaptation of The Hunchback of Notre Dame, directed by Gary Trousdale and Kirk Wise, who had also steered his performance in the film version of Beauty and the Beast.

From 1995 to 1996 Jay was the voice of the alien warlord Lord Dregg, the villain during the last two seasons of the original 1987 Teenage Mutant Ninja Turtles animated TV series.

He is also well known among fans of the 1996–2003 video game series Legacy of Kain for his voicing of the original Mortanius and of the Elder God, alongside several other minor characters.

In 11 episodes spanning 1990–91, Jay voiced Shere Khan for Disney's animated TV series TaleSpin,[27] The Jungle Book: Rhythm and Groove videogame (2000), and House of Mouse (2001–02).

On it Jay recites lyrics written by the likes of Noël Coward, Ira Gershwin, and Oscar Hammerstein, accompanied by synthesized music which he composed.