Initially projected as a late third rounder, Roos was selected with the ninth pick of the second round of the 2005 NFL Draft out of Eastern Washington. This made him the first Division I-AA player to be drafted that season and the highest draft pick ever to come out of Eastern Washington. In 2008, Roos was elected to the Pro Bowl and was first team All Pro.
On April 26, 2008 Roos signed a 6 year, $43 million extension with the Tennessee Titans.
Roos married his college girlfriend, Katherine Fossett, on July 9, 2006.
He does not speak Estonian, but his mother does. The Rooses donated $500,000 to their alma mater, Eastern Washington University, to "jump start" the school's stadium project, which included converting their football stadium from natural grass to red turf.
Because of the gesture of Roos and his wife, Eastern Washington University's Board Of Trustees approved a name change of their stadium to Roos Field.