In his first year with the Pittsburgh Steelers, Farrior recorded 82 tackles throughout 14 games. In 2003, he recorded 141 tackles and one interception. During the 2004 season, his third with the franchise, Farrior made 94 tackles, three sacks, and a career-high four interceptions. He also finished second behind Ed Reed for NFL Defensive Player of the Year honors. During the Pittsburgh Steelers 2005 campaign Farrior missed 2 games due to injury, but performed well in the 14 regular season games and 4 post-season games in which he appeared. His best regular season performance came in a week 3 loss to the New England Patriots, in which he recorded 9 tackles and 1 sack. Farrior’s best performance in the post-season came in the AFC Divisional playoffs against the Indianapolis Colts, where Farrior recorded 10 tackles and 2.5 sacks. He finished the season with 119 tackles and a Super Bowl ring. In 2006, he played in all 16 games and recorded 126 tackles, four sacks and one interception. Farrior finished the 2007 season with 94 tackles and 6.5 sacks, a career-high, along with one interception. Entering the 2008 season, Farrior stated that he wished to remain a Steeler for the remainder of his career. In August 2008, Farrior signed a five-year, US$18.25 million contract with the Steelers. The deal included a $5 million signing bonus. He was released on March 2, 2012.