He played Private Daniel Jackson in Saving Private Ryan (1998), Corrections Officer Dean Stanton in The Green Mile (1999), Roger Maris in 61* (2001), Joseph L. Galloway in We Were Soldiers (2002), Sergeant Michael Strank in Flags of Our Fathers (2006), DEA Agent Cooper in Snitch (2013), Vince in Maze Runner: The Scorch Trials (2015) and Maze Runner: The Death Cure (2018), Lucky Ned Pepper in the remake of the western True Grit (2010) and David Keller in Crawl (2019).

Pepper was born the youngest of three boys in Campbell River, British Columbia, the son of a lumberjack.

[3][2] Pepper attended Camosun College after receiving a scholarship for artistic achievement,[3] studying marketing and design.

He spent four years studying, including at the Gastown Actors Studio, before landing a recurring role on the show Madison.

Pepper provided the voice for Alex Mercer, the protagonist of the video game Prototype and the voice for Corporal Dunn, a character in the video game Call of Duty: Modern Warfare 2. Pepper won the Golden Raspberry Award for Worst Supporting Actor for his performance in Battlefield Earth: A Saga of the Year 3000.