Through the summer and into September, the Knicks pursued Donovan Mitchell with a fervor. 

He was the object of their affection, a local star who wanted to return home. Experts saw it as a certainty that the former Louisville star would eventually don the orange and blue and form a potent 1-2 backcourt punch with Jalen Brunson. 

Instead of the Knicks and Jazz working out a trade, however, Mitchell was sent to the Cavaliers, and in a twist of irony, his first postseason series with Cleveland will come against his hometown team. 

It is the best storyline of the opening round of the postseason: Mitchell against the surprising Knicks, the Elmsford, N.Y., native taking on the team that so badly wanted him to be a key part of its future. 

“It’s full circle. Wouldn’t want it any other way,” the four-time All-Star, who averaged a career-best 28.3 points this season, said recently. “What kid wouldn’t want to grow up and play against his hometown team in the playoffs? 

“I think it’s something that’s really special and near and dear to me being able to play in a playoff [series] in front of my friends and family. A team that I grew up watching. Against a guy that’s an assistant coach over there [Johnnie Bryant] who kind of basically taught me everything I know at this point. So it’s great. I’m excited for the challenge.” 

When it became apparent the Jazz were going to strip down their roster after a first-round playoff loss to the Mavericks in which Brunson carried Dallas, Mitchell was seen as likely headed to the Knicks.

Their president, Leon Rose, was once his agent.

The 26-year-old Mitchell had — and still has — a close relationship with Bryant dating to Bryant’s time with the Jazz.

The Knicks were loaded with assets, young players and draft picks. 

But after extended trade talks between the two sides, it never came to fruition.

The Jazz wound up getting a massive haul from Cleveland: Collin Sexton, Lauri Markkanen, Ochai Agbaji, three first-round picks and two pick swaps.

It was seen as a strong return at the time, and has only gotten better, after Markkanen’s breakthrough season to become a Most Improved Player award candidate. 

What exactly went wrong for the Knicks in their pursuit of Mitchell remains uncertain.

There were reports the Knicks and Jazz were unwilling to agree on the amount of unprotected first-round picks and disagreements on which players the Knicks would include.

ESPN’s Adrian Wojnarowski reported that the Knicks were unwilling to include Quentin Grimes along with RJ Barrett and draft picks, and sought to put Immanuel Quickley in the deal instead.

The Post reported at the time the Knicks didn’t want to send the Jazz three unprotected first-round picks. 

“On [Sept. 1], I went to sleep like, ‘OK I’m on the Knicks. I’m going to New York and I’m building a house back home,’ ” Mitchell said on ‘The Old Man and the Three’ podcast with JJ Redick and Tommy Alter. 

The next day, he was headed to Cleveland.

Rose drew heavy criticism early in the season, as the Knicks got off to a 10-13 start and seemed to be missing a closer like Mitchell in tight games.

In their first game against the Cavaliers, Mitchell poured in 38 points, notched 12 assists and was dominant in the fourth quarter of a 13-point win in Cleveland on Oct. 30. 

“We have to do better, and we will,” coach Tom Thibodeau said that night. 

He was right.

The Knicks became one of the biggest surprises in the league, easily topping their preseason over/under win number of 39.5 with 47 victories and finishing fifth in the Eastern Conference.

Brunson, an All-Star Game snub, lapped expectations while Julius Randle enjoyed a strong bounce-back season.

Those young players the Knicks hung on to by not trading for Mitchell — especially Quickley, a Sixth Man of the Year front-runner — were pivotal factors in the Knicks recording their most wins in a single season in a decade.

They beat the Cavaliers in each of their last three meetings and prevailed without an injured Randle in the last one, mostly because Brunson produced a superhuman 48-point effort. 

Mitchell has seen that before.

Brunson averaged 27.8 points in the Mavericks’ series victory over Utah last April, six games that played a major part in the Jazz breaking up their team.

The two were viewed as potential teammates for much of the offseason, particularly after Brunson signed with the Knicks.

It would’ve been a dream scenario. 

Now, it could turn out to be a nightmare for the Knicks, getting eliminated by the player they couldn’t land who wanted to come home.