McCown will transition into a role as an NFL analyst for ESPN and will debut on Wednesday.
The retirement announcement comes 17 seasons after he was a third-round pick in 2002 out of Sam Houston State. The journeyman signal-caller played for the Arizona Cardinals, Detroit Lions, Oakland Raiders, Carolina Panthers, Chicago Bears, Tampa Bay Buccaneers, Cleveland Browns and New York Jets during his career.
In 99 games at quarterback, he completed 60.2 percent of his passes for 17,707 yards, 98 touchdowns and 82 interceptions.
McCown's 2017 season with the Jets ended when he broke his hand in a December loss to the Denver Broncos. He had already set career-highs with 2,926 passing yards and 18 touchdown throws in 13 games before the injury and was well on his way to the first 3,000 passing yards season of his NFL tenure until the untimely setback.
He didn't get to build on that in 2018, though, as the Jets turned toward rookie Sam Darnold under center.
McCown surpassed the 2,000-yard mark four times in his career, with three coming in the only years he appeared in double-digit games (2004, 2014 and 2017).
The veteran told reporters he was undecided whether he would retire or not following the 2018 season and had to discuss his options with his family. He ultimately chose to hang up the spikes after a career that has largely been defined by his role as a solid quarterback option who could serve as a backup, injury replacement or stopgap until a team found its franchise guy.
While it appeared as if he was finally settling into a starting role in 2017 before the injury, Darnold is the Jets' future at the position. McCown chose retirement instead of an uncertain future as a soon-to-be 40-year-old unrestricted free agent.