The Oregon native sought a return to the West Coast and is familiar with San Diego. Clemens' wife, Nicole, attended the University of San Diego and has family and friends in the area.
Clemens also heard good things about the Chargers' organization from friend Danny Woodhead. Both played together with the New York Jets. Clemens was a second-round selection by the Jets in the 2006 draft.
"He's a hard worker," Clemens said about Woodhead. "He's a pro, and he understands the game. He has a high IQ. All he needed was an opportunity. And I'm excited to get another opportunity to play with him."
Location and a good locker room environment were selling points, but the clinchers for Clemens proved a chance to work with Philip Rivers and an opportunity to compete for a Super Bowl.
Clemens believes he achieved both by signing with San Diego.
"The guys in the quarterback room are people I'm going to be spending a lot of time with, so it's real important," he said. "Obviously, Philip brings a level of professionalism, toughness and maturity. And I'm excited to work with him."
Clemens said he enjoyed watching the Chargers make their surprising postseason run from afar last season.
"I like the direction the team his headed, making that playoff run and winning in the wild-card round," he said. "Going on that great run at the end of the season shows a lot."
With Charlie Whitehurst moving on in free agency to Tennessee, San Diego didn't bring Clemens in just to hold a clipboard. The 30-year-old University of Oregon product can win games if called upon.
Clemens showed that important characteristic last season. In 2013, he subbed for an injured Sam Bradford, leading the St. Louis Rams to a 4-5 record. Clemens threw for nearly 2,000 yards, eight touchdowns and seven interceptions.
While some of the concepts are familiar, Clemons will be learning San Diego's offense from scratch, having just gotten the playbook this week.
"I work hard, and I think I'm a pretty good teammate," Clemons said. "I'm not going to be any problem in the locker room, that's for sure. There's a passion I have for the game that hopefully is a little contagious."