The Swede moves across from iSport, where he spent the last two years, taking 10th and eighth in the championship.
Ericsson will be joined by Stephane Richelmi, who finished 18th in his first full GP2 season with Trident last year.
"I'm extremely proud to get the opportunity to drive for DAMS," said Ericsson, who is entering his fourth year in GP2.
"Their results over the last couple of years [winning titles with Romain Grosjean and Davide Valsecchi] say it all.
"After testing successfully together in the Jerez post-season tests, there were no doubts as to where I wanted to be in 2013.
"The preparations for next year have already started and I feel ready to fight at the front of the championship together with DAMS."
DAMS CEO Jean-Paul Driot believes that the French outfit has set itself up for another successful season.
"We've been GP2 champions for the last two years and we're hungry for more titles," said Driot.
"We had to recruit drivers capable of keeping us at this level and that's why I'm delighted that Marcus and Stephane have signed with us.
"Both have experience in GP2 and they're bringing the perfect combination of maturity and fieriness.
"I'm convinced that we're going to enjoy another great season in GP2 with them."