[1] His father, Homayoon Pasdar (Persian: هومایون پاسدار; born 1935), was an Iranian-American cardiac surgeon, with a practice near Philadelphia.

He graduated from Marple Newtown High School, where he went by his middle name Kayvan and where he played football and studied acting.

[2] Pasdar turned his attention to campus stage productions and rediscovered an early interest in writing and acting.

No longer able to play football, he dropped out of school and returned home, taking a job with a theater group, People's Light and Theatre Company.

Pasdar was also selected to play a bit part as a police officer in the Dixie Chicks video for their song "Goodbye Earl".

In 1992, he left Hollywood and returned to New York, working as a cashier for room and board, while taking the occasional small part, such as Frankie in Brian De Palma's Carlito's Way (1993).

The $1.7 million independent feature, which won Best Picture awards on the festival circuit, starred Chris Penn, Jeffrey Wright, Sherilyn Fenn, and Henry Czerny, and was written by Farscape screenwriter Justin Monjo.

From 2000 to 2002, Pasdar played the lead role of anthropology Professor Declan Dunn in the spooky cult drama series Mysterious Ways on PAX.

Having also voiced Iron Man in the English dub of the Iron Man anime series, Pasdar reprised the role in Marvel's Avengers Assemble (seasons 1–3), Ultimate Spider-Man, and Hulk and the Agents of S.M.A.S.H..[12] Pasdar also played a role on The Lying Game as Alec Rybak, a corrupt district attorney.

[20] Acting Directing Other In 2010, Pasdar narrated an audiobook edition of the cult novel Queer Fish in God's Waiting Room by the British writer Lee Henshaw.