"I felt I wasn't done here," Murray told ESPN's Joe Schad. "I still had some more things I wanted to get accomplished with my teammates and become a better player as well."
Murray is one of the most explosive players in college football when healthy. But he has been plagued by injuries throughout his career.
"I won't have to share carries anymore so I will get to play a lot more than I have here and be the guy," Murray said. "My mom wanted me to walk [graduate] as well."
Murray was held out of one game and missed time in others in 2009 with a midseason ankle injury. He finished with career lows in rushing with 705 yards and eight touchdowns.
In three seasons, Murray has run for 2,471 yards and 35 touchdowns.
Murray has split the Sooners' rushing load throughout his career with Chris Brown, who followed his 1,220-yard, 20-touchdown junior season with 749 yards and seven TDs in 2009.
Information from ESPN college football reporter Joe Schad was used in this report.