He replaces Steve Pederson, who parted ways with the school in December.
The 52-year-old Barnes will be in charge of helping the Panthers gain traction in the ACC, particularly in football. Pitt is on its fourth head football coach since 2010 after hiring Pat Narduzzi in December. The school says Barnes was a unanimous choice from the pool of candidates.
Barnes has been the AD at Utah State since 2008, and he just completed his term as NCAA men's basketball committee chairman earlier this month. The Aggies have gone to four consecutive bowl games under coaches Gary Andersen and Matt Wells.
Barnes, who was previously the senior associate athletic director at Washington, promoted assistant coach Tim Duryea last month to replace longtime Utah State men's basketball coach Stew Morrill, who retired after this past season.
The Associated Press contributed to this report.