"For me, the next chapter isn't just about what I can do as an individual, but what I can give back to cycling as a sport," said Horner in a team statement.
"I had a number of options for this year and what really struck me about Airgas-Safeway was their utter commitment to giving the next generation of young riders the opportunity for success.
"Racing with excited young athletes fits well with my love of the sport, and it will be a great partnership to build for the future. I look forward to sharing my racing and tactical experience to help the team race for the win at Tour of California, Tour of Utah, and many other races throughout the season."
The 43 year old has been searching for a new team since being told his contract with current team Lampre-Merida would not be renewed. The American won the Vuelta a Espana in 2013, becoming the oldest Grand Tour winner in history but struggled to find a team for the 2014 season after bungling negotiations with a number of teams.
He found a reprieve when Baden Cooke, acting unofficial agent for the American, brokered a deal with Lampre, who he joined early in the season.
Horner has since had a tough year, suffering a major setback when he was hit by a car while training in Italy in April, and then was obliged to sit out the Vuelta a Espana due to high cortisol levels.
