One of college football's most explosive receivers, Green-Beckham had a breakout season for the Tigers in 2013 with 59 receptions for 883 yards and 12 touchdowns as a sophomore. He was one of the nation's top recruits in the Class of 2012, ranking No. 3 on the ESPN150.
"We are pleased to welcome Dorial to the University of Oklahoma, where he is excited to continue his education and resume his playing career," Sooners coach Bob Stoops said in a statement. "Dorial understands the privilege and responsibilities of representing the Oklahoma football program. He is a talented young man who is eager to get to work with the rest of our team in the classroom and on the field."
A source said Green-Beckham signed with the Sooners on Wednesday and was essentially going through an orientation process on Thursday in preparation for Oklahoma's July summer school session which begins next week.
Green-Beckham is exploring if there is any way he can get a waiver from the NCAA to play this season, a source told ESPN's Joe Schad.
Oklahoma's waiver to the NCAA on behalf of Green-Beckham will be based on an NCAA "run-off" rule. Using this rule, former LSU point guard Anthony Hickey became immediately eligible to play at Oklahoma State after being dismissed by the Tigers.
Green-Beckham's admission to Oklahoma came with specific stipulations including continued rehabilitation and drug testing, according to a source. Green-Beckham will be subject to a "zero tolerance" policy which includes any failed drug test.
Oklahoma believes it has the resources to help Green-Beckham. There was "due diligence" communication between Oklahoma and Missouri coaching staffs before Oklahoma -- including the athletic director and president's office -- approved the transfer.
The 6-foot-6 Green-Beckham was kicked out of Missouri's program after an initial suspension. His troubles included being investigated for allegedly pushing an 18-year-old Missouri student down at least four stairs. No charges were filed and the case was closed after the student and a roommate declined to press charges.
Green-Beckham also had two marijuana-related arrests during his time at Missouri.
"I appreciate this opportunity from Coach Stoops and the University of Oklahoma," Green-Beckham said in the statement issued by the university. "There are people here who will help me build a strong foundation. I've disappointed myself and others in the past. I know that I have a lot of work to do and I'm ready to get started."
The Sooners have been searching for impact players at the receiver position. Sterling Shepard was the lone proven receiver on the roster. OU was one of the finalists for Green-Beckham out of high school, as he made several visits to Norman, Oklahoma, before the 225-pound receiver eventually picked Missouri.
Information from ESPN.com's Jake Trotter and Joe Schad was used in this report.