The Jets waited until Marshall passed his physical before parting ways with Harvin, whose ouster was announced simultaneously with confirmation of the trade.
There was a late detail on the trade. In addition to Marshall, the Jets also received a seventh-round pick from the Chicago Bears, according to ESPN NFL Insider Adam Schefter. They sent a fifth-rounder to the Bears, as previously reported.
"At this point in my career, I've still got 10 more years left in me," Marshall said in a statement. "It's the same thing from day one. I'm just trying to get better at everything possible. I can still do everything, and I'm excited to do that. There's going to be more on my plate.
"Paired up with [Eric] Decker and [Jeremy] Kerley, I'm looking forward to working with those guys, and working in this offense with what [coordinator] Chan Gailey is asking us to do, it's going to give us more opportunities to make plays.
"Chicago was a little different, but it was a great offense and great people, and I'm looking forward to creating that same bond with the guys here on offense."
Harvin, 26, once regarded as a rising star in the NFL, will be looking for his fourth team in four years. He played only eight games with the Jets after arriving in a midseason trade with the Seattle Seahawks.
The trade compensation is now final; the Jets will send their sixth-round pick to the Seahawks. If they had kept Harvin on the roster until March 19, it would have escalated to a fourth-round pick.
A source told ESPN's Josina Anderson that Harvin will visit with the Bills Wednesday, where he could be reunited with former Jets coach Rex Ryan.
By releasing Harvin, who had four nonguaranteed years left on his contract, the Jets will save $10.5 million on the salary cap. They are not stuck with any "dead" money.
Last year's acquisition of Harvin was called "a potential coup" by former general manager John Idzik, who made a desperation deal in October to breathe life into the moribund Jets.
Harvin became an immediate starter and contributed two 100-yard receiving days, but he finished with only 29 catches and one touchdown.
The Jets approached Harvin recently about taking a pay cut, an indication they considered him overpriced at $10.5 million in 2015. In addition, they wanted to find a more traditional receiver than Harvin, a gadget-type player who works best out of the flat on screen passes.
The search led them to Marshall, and it will cost the Jets a fifth-round pick. It means the Jets will have no fifth- and sixth-round choices in the coming draft.
Much like Marshall, who has been traded three times, Harvin has endured a tumultuous career. He was an all-purpose threat for the Minnesota Vikings from 2009 to 2012, but he was injury prone and clashed with coaches, so he was traded to the Seahawks.
Harvin missed most of the 2013 season with a hip injury, but he returned for the Super Bowl and contributed to the win by scoring on a kickoff return. By last season, the Seahawks grew weary of Harvin, who reportedly became a divisive influence in the locker room.
He was well-behaved during his brief time with the Jets.
"Percy is a talented player who has been a model teammate with the Jets," general manager Mike Maccagnan said. "We've made it clear to Percy and his representatives that we are open to a potential return if there is an arrangement that works for both sides, but out of respect for Percy, we want to give him an opportunity to test the market and evaluate his options."
Even though the Jets didn't rule out the possibility of re-signing Harvin, they would have to wait until the second day of the draft. Otherwise, the draft-pick compensation would be a fourth-rounder, per the conditions of last year's trade.
In his career, Harvin has 332 receptions for 3,802 yards and 21 touchdowns. He also has 10 touchdowns on rushes and kickoff returns.