Decker, 30, has owned a home in the Nashville area since 2012 with his wife, country music star Jesse James Decker.
"It was kind of a perfect storm," Decker told the team's website on Monday. "You only get so many years to play this game, and I wanted to find the right fit. I wanted to come to a place where I can help out, and this is home.
"There were a lot of factors. This is a team on the rise, and I like the coaching staff, the GM, and the philosophy upstairs. I like the quarterback, the locker room and the mentality. When I talked to the GM and the coaches, finding out what they wanted out of me, what my role would be, Tennessee was the best opportunity."
Decker was released by the Jets last Monday, and two days later he visited with Tennessee officials, including general manager with Jon Robinson and head coach Mike Mularkey.
Decker played only three games last season for the Jets before being placed on injured reserve in October. He suffered a partially torn rotator cuff early in the season, limiting him to nine receptions for 194 yards and two touchdowns. In 2015, he had 80 catches for 1,027 yards and 12 TDs for the Jets.
Decker has undergone surgery on both his hip and his shoulder in the past nine months.
The Titans needed an established wide receiver to pair with quarterback Marcus Mariota.
The 6-foot-3, 214-pound Decker, a third-round pick of the Broncos in the 2010 NFL Draft, owns 385 career receptions for 5,253 yards and 52 touchdowns in seven seasons. He has three 1,000-yard receiving seasons in his career, including a 1,288-yard season in 2013. He also has turned in a dozen 100-yard performances.
Decker said he talked with a number of other teams and scheduled other visits this week before opting to sign with the Titans.
"Mulling over some of my options, I just felt like this was the right fit," Decker said. "Just looking at the roster, and the progress they've made over the last few years, and meeting with Jon (Robinson) and Mike (Mularkey), I have a lot of respect for where they came from, their philosophy, how they do things, and that's something I want to be a part of.
"And I am excited about Marcus Mariota and the young talent he is."