Ornstein studied acting as a child at the American Academy of Dramatic Arts in New York City, and later studied under Stella Adler. After high school, he enrolled in the Mason Gross School of the Arts. He quit after his first year and moved to New York City to begin working professionally.
Ornstein's first film credit was in Crossing Delancey, where he played the minor character "Mickey". Television credits include a recurring role as Detective Bonnaventura on Homicide: Life on the Street, and a two-episode arc on Third Watch, as well as parts in Seinfeld, Law & Order, Law & Order: Special Victims Unit, and Law & Order: Criminal Intent.
Ornstein's stage acting credits span twenty-five years worth of new plays in New York City, in addition to creating the role of Louis Ironson in the 1991 World Premiere of Angels in America at the Eureka Theater in San Francisco.
Ornstein plays Chuck Marstein on Sons of Anarchy.
2022
as Butcher
2018
as Chuck 'Chucky' Marstein
2017
as Lorenzo Santella Jr.
2017
as Kal Barko
2015
as Mordecai
2009
2008
as Chuck 'Chucky' Marstein
2008
as 'Chucky' Marstein
2001
as Howard
2001
as Philip
2001
as Florist
1999
as Lenny Ellis
1999
1999
as Charles Denis
1998
as Computer Wizard
1996
as Jackie Ciro
1995
as Mike Miller
1993
1993
as Det. Sartucci
1990
as Sklar
1990
as Eugene Miller
1989
as Waiter
1988
as Mickey