
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.

Law & Order
TV • 1990

Law & Order
TV • 1990

Law & Order: Special Victims Unit
TV • 1999

NCIS: Los Angeles
TV • 2009

Seinfeld
TV • 1989

Law & Order: Criminal Intent
TV • 2001

Law & Order: Criminal Intent
TV • 2001

Law & Order: Criminal Intent
TV • 2001

Sons of Anarchy
TV • 2008

Third Watch
TV • 1999

Homicide: Life on the Street
TV • 1993

Mayans M.C.
TV • 2018

Good Game
TV • 2017

Blindsided
MOVIE • 1993

The Saint
MOVIE • 2017

Mosquito
MOVIE • 2022

Kansas City
MOVIE • 1996

Crossing Delancey
MOVIE • 1988