Kingsbury, 33, was offered the Tech job on Wednesday afternoon, and athletic director Kirby Hocutt announced the news of him accepting it with a video posted on Twitter not long after.
"Wreck 'em Tech," Kingsbury said in the video, giving the school's "Guns Up" sign when the camera panned to him.
Kingsbury was Texas A&M's offensive coordinator and quarterbacks coach. He instructed Heisman Trophy winner Johnny Manziel this season.
Hocutt said Kingsbury agreed to a four-year deal, the terms of which have not been settled. Kingsbury will be formally introduced at a news conference on Friday.
"It's just been a whirlwind, but I couldn't be happier, beyond ecstatic to be back. It feels like home," Kingsbury said after landing in Lubbock on Wednesday night. "This is where I wanted to be; it's where I've wanted to be."
Hocutt called Kingsbury the "right fit" for Texas Tech.
"He's prepared his whole life for this," said Hocutt, who was the same age as Kingsbury when he got his first athletic director job at Ohio University. "He's ready and I had no hesitation."
Kingsbury was co-offensive coordinator and quarterbacks coach for Houston and record-breaking QB Case Keenum in 2010-11.
Kingsbury threw 95 touchdowns for Texas Tech between 1998-2002.
Kingsbury has been mentored by successful coaches such as Dana Holgorsen and Kevin Sumlin, who stressed Kingbury's organization and intelligence despite his inexperience.
The Texas Tech job came open when Tommy Tuberville left in stunning fashion Saturday, ending his three-year tenure in Lubbock to become Cincinnati's coach.
Red Raiders fans never warmed to Tuberville. Texas Tech still emphasized the passing game and the spread offense, but many Tech fans had a hard time getting past the firing of the popular Mike Leach.
There's no doubt about what kind of offense the Red Raiders now will run. Kingsbury has been part of some of the most prolific offenses in the country the past few years. Texas A&M is third in the nation in total offense at 552 yards per game heading into the AT&T Cotton Bowl against Oklahoma.
"Bittersweet..happy for him though couldn't of happened to a better guy and a great coach," Manziel wrote on Twitter. "To all the people worried about Coach K leaving..Coach Sumlin will always bring in the best and do anything to make sure we're successful ... Have faith in Coach Sumlin...It's got us this far, why stop now?"
If it was any other school, Kingsbury said, he would have stayed at A&M.
"He understands," Kingsbury said of Manziel. "He knows how I feel about him. He's as good a player as I've ever seen and probably the fiercest competitor I've ever been around, so it was definitely hard with that. But this is where I belong."
Kingsbury will work with sophomore quarterback Michael Brewer, this season's backup to Seth Doege. Brewer played high school football under Chad Morris, who Hocutt interviewed for the Red Raiders coaching job Tuesday in South Carolina. Hocutt later flew to Nashville, Tenn., to meet with Titans defensive coordinator Jerry Gray.
Kingsbury knows Brewer's talent, calling him a "winner" and a "heck of a player."
"I just got through coaching one of those up that was pretty decent, so hopefully we can get him going," he said of Brewer.
The past two seasons have seen the Red Raiders slide down the stretch. This year they lost four of their last five games, and in 2011, they dropped five straight to close the season for the program's first losing season since 1992. Under Tuberville, Texas Tech did not have a winning Big 12 season.
The Red Raiders play Minnesota in the Meineke Car Care Bowl on Dec. 28 in Houston. Chris Thomsen, who led the offensive line under Tuberville, will coach that game.
He is a Texas native from New Braunfels, not far from Austin.
Information from The Associated Press was used in this report.