Assistant Coach Tony Levine has been named interim head coach at Houston, officials said.
Sumlin told his team that he was leaving in a meeting on Saturday. UH Director of Athletics Mack Rhoades and Levine then held a press conference to make the announcement.
Sumlin's name came up in College Station as soon as Mike Sherman was fired nine days ago. Some had it happening as early as last weekend. The Aggies, though, decided to talk to multiple candidates before officially offering the job to Sumlin.
Texas A&M did not make their offer until early Saturday morning, we are told.
Rhoades said he gave Sumlin a handshake and a hug and wished him good luck Saturday morning, and he's hoping that's what the fans will do during this transition.
He also said he called the Aggies' athletic director and told him they made a great choice with Sumlin.
"[This is] an emotional time for everyone," Rhoades said, adding that Sumlin is leaving the program in much better shape than it was in when he arrived.
Houston was undefeated for their first 12 games this season and the team was in line for a Bowl Championship Series berth until losing to Southern Mississippi at home in the Conference USA championship game.
According to Rhoades, the university's top priority now is making sure the 120 student athletes handle the transition well.
Levine said they are also focusing on players' academics as they begin final exams, recruiting -- Friday is the first major recruiting weekend -- and preparations for the TicketCity Bowl game against Penn State in Dallas on January 2.
Another item on the university's agenda: finding a new permanent head coach.
Rhoades said UH will waste no time in launching a national search for Sumlin's replacement, adding that he will not discuss any internal or external candidates publicly.
Rhoades did not comment on whether Sumlin has expressed interest in taking any assistant coaches with him. He says Levine has committed to stay through the game with Penn State.
Sumlin is taking over an Aggies team that underachieved, going 6 and 6 this season. They'll take on Northwestern in the Meineke Car Care Bowl on New Year's Eve at Reliant Stadium