Terms of the contract weren't immediately available.
Patton, 26, set career highs last season with 37 catches and 408 yards, playing 68 percent of the offensive snaps for the 49ers. He became expendable when they re-signed Jeremy Kerley and added Pierre Garcon and Marquise Goodwin.
This was the Jets' first addition at wide receiver. Previously, they released Brandon Marshall, their leading receiver in each of the last two seasons.
Right now, the Jets' top receivers are Eric Decker and Quincy Enunwa. Decker is recovering from hip and shoulder surgeries and, although he's expected to be ready for training camp, his roster spot isn't secure.
Patton, a fourth-round pick of the 49ers in 2013, will be reunited with his first position coach, John Morton, the Jets' new offensive coordinator.
Patton, who started 14 games for San Francisco in 2016, drew praise from the Niners coaching staff for his blocking ability in the run game.
ESPN's Nick Wagoner contributed to this report.