Joyner said that long-time defensive line coach Larry Johnson will serve as interim head coach while the search is underway.
"We need to do everything we can to support the needs of our student-athletes during this period," Joyner said. "I am very confident in Larry Johnson, the coaches and staff in maintaining continuity and working with the returning players and recruits. "We intend to move quickly in our search to identify the next great Penn State football coach," Joyner added.
"I'm humbled by the confidence that Penn State has bestowed upon me during this critical time for the football program and honored to do my part to help Penn State," Johnson said. "My job will be made very easy since we have a team comprised of tremendous student-athletes, coaches, trainers and support staff who are second to none and care as much about Penn State as I do. This program has a historic past and very bright future and I look forward to continuing to work with the players, staff and our incoming recruiting class to uphold the tremendous traditions, ideals and principles that make Penn State the best University in the nation and the football program the most successful on and off the field."
O'Brien led Penn State to marks of 8-4 and 7-5 during his two years as the Nittany Lions' head coach. In 2013, he helped develop three first-team All-Big Ten honorees -- DT DaQuan Jones, WR Allen Robinson and G John Urschel. In addition, Robinson was selected a first-team All-American, as well as the Big Ten Richter-Howard Receiver of the Year for the second consecutive year. Quarterback Christian Hackenberg was named Big Ten Freshman of the Year, giving Penn State the conference's last two freshman honorees.
During the 2012 season, O'Brien was selected the Bear Bryant, Maxwell Football Club and ESPN National Coach of the Year and the Big Ten-Dave McClain Coach of the Year and Hayes-Schembechler Coach of the Year. O'Brien's eight wins were the most by a first-year Penn State coach in the history of the program, which began in 1887.
O'Brien came to Penn State after five years on the New England Patriots' coaching staff, serving as the quarterbacks coach from 2009-11 and as offensive coordinator in 2011, helping the Patriots to the AFC Championship and a berth in Super Bowl XLVI. O'Brien began his coaching career at his alma mater, Brown University, in 1993-94. He then coached at Georgia Tech (1995-2002), Maryland (2003-04) and Duke (2005-06) before joining the New England staff.
The Nittany Lions return 16 starters for the 2014 season (8 offense, 7 defense, 1 specialist), which begins August 30 vs. No. 15 UCF in the Croke Park Classic in Dublin, Ireland.