Titans president and CEO Tommy Smith called the hiring a big day in announcing the hiring Monday.
Whisenhunt, 51, will be introduced at a news conference Tuesday.
The Titans flew to San Diego on Friday and interviewed Whisenhunt, who started his coaching career in Nashville at Vanderbilt. He was the fourth person interviewed by the Titans, who fired Mike Munchak on Jan. 4.
But the Titans had competition for Whisenhunt, who also interviewed with Detroit and Cleveland last week. The Tennessean reported the Titans interviewed Cincinnati defensive coordinator Mike Zimmer for a second time Monday in Houston before hiring Whisenhunt.
Smith thanked general manager Ruston Webster for overseeing only the second coaching search by this franchise since moving to Tennessee in 1997. Webster said Whisenhunt's intelligence, track record with quality offenses and success as a head coach stand out to him most.
"I really enjoyed our meeting on Friday night in San Diego, and we share similar philosophies about the game," Webster said.
"Additionally, we have several mutual colleagues that have spoken highly to me about Ken both as a coach and as a person. I am excited about Ken joining us and the future of the Titans."
Whisenhunt spent six years coaching Arizona and took the Cardinals to their lone Super Bowl in 2009. He was fired Dec. 31, 2012, with a record of 45-51 in the regular season and 4-2 in the playoffs.
He interviewed with Cleveland twice last year before being hired as offensive coordinator in San Diego where he helped Philip Rivers and the Chargers to the playoffs.
Chargers rookie head coach Mike McCoy said earlier Monday before the Titans hired Whisenhunt that he didn't want to lose his coordinator but realized he might lose him after only a year.
"Ken has done an outstanding job here this year," McCoy said. "He is a big reason of why we got as far as we did, not only on the field, but behind the scenes with things that he did to help me."
Tight end Antonio Gates said Whisenhunt did a phenomenal job implementing a new offense in San Diego that put them in the best position possible.
"It was a privilege and a pleasure to be around a guy of that stature with the experience and winning Super Bowls, and then helping me grow as a player," Gates said.
Whisenhunt, a native of Augusta, Ga., played tight end at Georgia Tech and played 74 games in nine NFL seasons with Atlanta, Washington and the Jets.
He started coaching in Nashville as an assistant at Vanderbilt and also was offensive coordinator for Pittsburgh between 2004 and 2006. He also has coached at Baltimore, the Jets and Cleveland.
The Titans were the last NFL team to fire a head coach, and this hiring leaves Minnesota, Detroit and Cleveland still looking for a head coach. They also interviewed Jay Gruden, who was hired Thursday as Washington's new coach and Baltimore offensive coordinator Jim Caldwell.
Tennessee parted with Munchak after going 7-9 this past season and missing the playoffs for the fifth straight season. This franchise has not won a postseason game since January 2003. But Tennessee ranks eighth in the NFL for the best winning percentage in the league since 1999 with a record of 131-108.
Whisenhunt takes over a team with questions about quarterback