Other lead roles include Here on Earth (2000), Say It Isn't So (2001), Rollerball (2002), Day Zero (2007), Street Fighter: The Legend of Chun-Li (2009), and Authors Anonymous (2014).

His notable supporting roles include Election (1999), We Were Soldiers (2002), The United States of Leland (2003), Just Friends (2005), and American Dreamz (2006).

In television, Klein has had main roles as Marty Tanner on the CBS sitcom Welcome to The Captain (2008) and Orlin Dwyer / Cicada on the CW superhero series The Flash (2018–2019).

Klein was born in Hinsdale, Illinois, and moved to Omaha, Nebraska, at age 13, and later attended Millard West High School.

Soon after, Klein found steady work in the film industry while briefly attending TCU, where he studied theater and was a member of the Lambda Chi Alpha fraternity.

He was next seen in American Pie, acting as Christopher Russell Ostreicher, which opened on July 9, 1999, and was a box office success.

[14] Klein was arrested for drunk driving on February 5, 2005, in San Diego County[15] and again in Los Angeles on June 16, 2010.