He is widely known for his television roles, notably Artie Nielsen on Warehouse 13, Donny Douglas on Frasier, Lon Cohen on A Nero Wolfe Mystery, and Louis B. Mayer on The Last Tycoon.

He also starred in the films Against All Odds (1984), Wall Street (1987), The Bonfire of the Vanities (1990), Unforgiven (1992), Nixon (1995), True Romance (1993), The Express (2008), Barney's Version (2010), and The Ballad of Buster Scruggs (2018).

[3] So Many Miracles, a book written by Rubinek and published by Penguin Canada in 1988, recounts his parents' experiences in Poland during the Holocaust.

[10] In 1982, he played Allan in the sex-themed romantic comedy Soup for One, directed and written by Jonathan Kaufer and produced by Marvin Worth.

Rubinek appeared in: Taylor Hackford's Against All Odds (1984); Alan Alda's Sweet Liberty (1986) as director Bo Hodges; Oliver Stone's Wall Street (1987), as a lawyer; The Outside Chance of Maximilian Glick (1988), as a fun-loving rabbi; Brian De Palma's The Bonfire of the Vanities (1990), again as a lawyer; and in a lead part as a rabbi in The Quarrel (1991).

He had a notable role in Tony Scott's True Romance (1993) as Lee Donowitz, a pompous, cocaine-addicted film producer based on Joel Silver.

Rubinek, an ardent Star Trek fan, abruptly took over the part after David Rappaport, the actor who was originally cast in the role, attempted suicide shortly after the filming of the episode had begun.

[12] He played Donny Douglas (Daphne Moon's fiancé and Niles Crane's divorce lawyer) in several episodes of the American sitcom Frasier.

Rubinek starred in the Syfy series Warehouse 13 as Artie Nielsen, a covert agent employed by a secretive council to recover mystical artifacts with his team.

[17] His first play, Terrible Advice, premiered in September 2011 at the Menier Chocolate Factory Theatre in London, starring Scott Bakula, Sharon Horgan, Andy Nyman and Caroline Quentin.