Rex is an ex.

The New York Jets fired Coach Rex Ryan on Monday, a day after the conclusion of their worst season since 2007.

And he wasn’t the only one to go. The club fired General Manager John Idzik, too, ending his two-year stint.

Ryan’s six-year career as Jets coach started with great promise, as he led the team to consecutive appearances in the AFC championship game. But the team failed to make the playoffs in each of the past four seasons.

“Both Rex and John made significant contributions to the team, and they have my appreciation and gratitude for their efforts and commitment,” Jets owner Woody Johnson said in a statement. “Over the years, Rex brought the Jets a bold confidence and a couple of great postseason runs, which all of us will remember.”

The Jets went 12-20 during the Idzik era, capped by this season’s 4-12 finish.

Why he got fired: Ryan was the only coach in franchise history to take the Jets to consecutive conference championship games, and for years he was largely adored by the fan base. But under him, the team couldn’t shake the reputation it was a dysfunctional organization. Nor could the Jets escape the long shadow of New England in the AFC East. Ryan’s teams finished 4-9 against the Patriots.

Fair or not: Jets owner Woody Johnson gave Ryan plenty of chances, including a one-year contract extension after last season’s team finished 8-8 with then-rookie quarterback Geno Smith. Instead of managing expectations, Ryan typically thumped his chest, announcing, “I’m so confident that I don’t care who knows it.”

Replacement candidates: Ryan was a defensive specialist, so the Jets might go with an offensive mind. There are plenty of offensive coordinators to choose from, among them Denver’s Adam Gase and Seattle’s Darrell Bevell, who have never been head coaches, or former head coaches such as Cincinnati’s Hue Jackson or Baltimore’s Gary Kubiak.

What the future holds: With or without Ryan, the Jets are still looking for their answer at quarterback, although Smith played well in Sunday’s 37-24 victory at Miami. As long as Tom Brady is in New England, it’s going to be very tough for any coach to topple the Patriots. Ryan, meanwhile, should not have a problem landing a head coaching job in another NFL city. At worst, he would make an excellent defensive coordinator somewhere.

Bears fire coach, GM

With the Chicago Bears locked in a downward spiral during his two seasons as coach, Marc Trestman was fired Monday.

Trestman, who inherited a 10-6 team from Lovie Smith in 2012, led the Bears to finishes of 8-8 and 5-11 before he was shown the door.

The man who hired him was let go too. The Bears also dismissed General Manager Phil Emery after two seasons.

The Bears, who haven’t made the playoffs since 2010, failed to beat a winning team this season and yielded 50 points or more in consecutive defeats, suffering a 51-23 loss to New England and a 55-14 loss to Green Bay.

Why he got fired: Since the end of the George Halas era, the Bears had never fired a coach after fewer than three seasons. That changed with Trestman, who was shown the door after two. This season was especially humiliating, with the club failing to beat a winning team, and a string of humbling defeats — including losses of 38-17 and 55-14 to the bitter rival Green Bay Packers. Trestman, whose specialty is working with quarterbacks, failed to turn Jay Cutler into a winner, and the franchise signed the quarterback to a seven-year, $127-million deal in January.

Fair or not: The Bears had to do something dramatic to begin to right the ship, and that meant giving Trestman and General Manager Phil Emery the boot. In Trestman’s two seasons, the Bears were 2-11 against teams with winning records. And the quarterback situation was an absolute circus. Trestman had clearly lost the locker room, and the whole mess had become an embarrassment. With arrows pointing up in the other three NFC North cities, the Bears needed to make a change.

Replacement candidates: If the Bears plan to stick with an offensive specialist, they could make a run at Indianapolis offensive coordinator Pep Hamilton, who was with Andrew Luck at Stanford then followed him to the Colts. If they go defense — the historic roots of that organization — they could take a hard look at Seattle defensive coordinator Dan Quinn, who oversees one of the most smothering units in football.

What the future holds: Much of the Bears’ immediate future hinges on what they do with Cutler, who initially improved under Trestman but recently has been in a tailspin. Because their housecleaning was complete — coach and general manager — they will have a fresh start on becoming competitive again in a division where Green Bay and Detroit have their quarterback answers, and Minnesota is bullish on Teddy Bridgewater.

Falcons’ Smith fired after 7 seasons

Mike Smith was the winningest coach in Atlanta Falcons history.

Ultimately, though, that didn’t save his job.

Smith was fired Monday after a 6-10 season and an utter collapse in a do-or-die finale against Carolina, a 34-3 home loss for the NFC South title.

Asked after the game whether Smith and his staff deserved to be retained, the coach was realistic.

“That’s not my choice,” he said. “This is a business about winning football games and that’s how you’re judged. I understand that and I’ll leave it at that.”

Smith was 66-46 in seven seasons. He took the reins after the tumultuous 2007 season during which quarterback Michael Vick was sent to federal prison for his role in a dog-fighting operation, and Coach Bobby Petrino quit 13 games into the season.

“Smitty’s contributions to our club, team and city over the last seven years are numerous,” Falcons owner Arthur Blank said in a written statement. “His accomplishments on the field made him the most successful coach in the 49-year history of the Falcons, and we are grateful for the foundation he has laid for us for the future.”