Mason, 37, cut last week by the Ravens, arrived Thursday morning, met with team officials, took a physical and returned to his Nashville home to make the decision. He knows coach Rex Ryan, a former Ravens assistant, from their years in Baltimore.
"After a lot of very thoughtful and careful consideration, conversations with my family and prayer, I have decided to sign with the New York Jets," Mason told ESPN NFL Insider Adam Schefter. "I'm looking forward to working under Rex and rejoining some familiar faces."
On Friday, Ryan didn't seem too optimistic about the Jets' chances, saying other teams wanted Mason, a 15-year veteran. His two former teams, the Ravens and Tennessee Titans, were also interested.
"I'm sure he'd have to leave money on the table to come here," Ryan had said.
The team had yet to make an announcement regarding Mason, but the deal is for two years, a source told ESPNNewYork.com.
The addition of Mason completes a stunning makeover to the Jets' receiving corps. Five days ago, they signed Plaxico Burress, who hasn't played in two years because he served 20 months in jail for weapons possession. They re-signed Santonio Holmes, but said goodbye to Jerricho Cotchery (released) and free agents Braylon Edwards and Brad Smith, who signed with the San Francisco 49ers and Buffalo Bills, respectively.
Mason has an impressive resume, including eight 1,000-yard seasons. His production dropped last year (61 catches, 802 yards), but he tied for the Ravens' team lead with seven touchdown catches.
Mason probably will be the Jets' No. 3 receiver, used in the slot. He's still quick in and out of his breaks and can be effective against zone coverage, according to one scout, but he will struggle to gain separation against man-to-man.
After choosing the Jets over the Ravens and Titans on Saturday, he wrote on his Twitter page: "Jet fuel is full time to fly!!!!"
Jets rookie receiver Jeremy Kerley, who's been wearing No. 85 -- Mason's number since his second year in the NFL -- tweeted that he'd give it up out of respect to Mason.
"Going from one young gun to another!! Hahahahahaha," Mason tweeted.
Mason is the only player in NFL history to produce at least 5,000 total return yards and 11,000 receiving yards, and his 924 career receptions rank 12th in NFL history. Mason owns the top three reception seasons in Ravens franchise history and also posted four of his eight career 1,000-yard campaigns in Baltimore, the other four coming with Tennessee, where he played for the first eight seasons of his career.
"I would like to thank my family for supporting this difficult decision I made today!" Mason wrote in a series of tweets. "For 14 yrs they have been by my side and they chose to do it yet again even though this time it was hard for them!! Also I would like to thank all of Baltimore for supporting me for the last 6 years!! U guys and gals have been my football family and I will forever appreciate that support and love!"
Rich Cimini covers the Jets for ESPNNewYork.com. Information from ESPN NFL Insider Adam Schefter and The Associated Press was used in this report.