Ridley had been suspended since March 2022 when the NFL found he had bet on games during a five-day period when he was not with his team, then the Atlanta Falcons. The Falcons traded him in November.
The former first-round pick is eligible to participate in all team activities, effective immediately, the NFL said.
"Today's reinstatement by the NFL brings an end to a challenging chapter of my professional career, one that was self-inflicted and began with an isolated lapse in judgment," Ridley said in a statement.
"I have always owned my mistakes and this is no different."
The league found no evidence that he had used "inside information" or compromised any game. Gambling is considered one of the most egregious offences a player can commit in the NFL.
The Jaguars said in a statement that they expect Ridley to participate in their off-season program in April.
"We look forward to building a relationship with Calvin as both an individual and as a player," the team said.
