Wright, 27, signed a one-year contract on Saturday. NFL.com reported the deal was worth $3 million, with an opportunity to make as much as $4 million.
The 5-foot-11, 182-pound Wright played at USC from 2006-10 and was selected by the Chargers in the third round of the 2011 draft.
"Truly blessed and honored to be part of the @49ers family, thank you #NinerEmpire for welcoming me," Wright wrote on Twitter.
Wright intercepted one pass last season.
Wright joins a 49ers team that includes center Marcus Martin and also tight end Xavier Grimble, who signed a reserve/future contract in December.