He played college football for the Alabama Crimson Tide, and was selected by the Baltimore Ravens 137th overall in the fourth round of the 2007 NFL draft.

McClain was considered one of the best fullbacks available in the 2007 NFL draft,[2][3] and drew comparisons to William Henderson.

He scored his first career touchdown on a Kyle Boller pass against the San Diego Chargers on November 25, 2007.

On December 20, 2008, McClain ran for 82 yards to score the final touchdown in Texas Stadium against the Dallas Cowboys.

McClain's performance earned him a Pro Bowl selection, in which he scored a touchdown off of a Fumblerooski play handed off by former Denver Broncos quarterback Jay Cutler.