It essentially began with a note on the door of a Miami housing project, signed by a reporter making one last try. I was looking for the mother of Gilbert Arenas, the abandoned boy who became an NBA superstar.

I was also looking for the story that would help me belong as a columnist here.

“My name is Mike Wise. I’m a reporter at The Washington Post,” I penned and taped to a door after no one answered.

Driving up and down the streets of Overtown, trying to find the missing piece of an athlete’s puzzled life as much as I was trying to find myself, I returned to the hotel feeling defeated, ready to check out and move on . . . when the phone rang.

Francis Robinson, who gave up Gilbert at 4 years old, came down the stairs of the apartment the next morning and let go of her guilt and pain. “I scarred Gilbert real bad,” she said through deep sobs. “I know I did. Not just him but myself, too. I scarred myself.”

Anyone looking to get to the heart of a story in Washington has had one guiding principle for the past 40 years: “Follow the money.” Me? I had better luck following the mother.

Whether it was Arenas, NHL enforcer Donald Brashear or Carlton Dotson, the kid from Maryland’s Eastern Shore who killed his teammate at Baylor, something about giving women who left their children room to talk and be heard yielded a better understanding of their boys than any coach or advanced metrics possibly could.

Unexpectedly finding Arenas’s mother in Miami, writing a story I’m still proud of, gave me an identity. Sometime later, Bonnie Berkowitz — a godsend of an editor — said, “You’re the heart-on-the-sleeve guy here. You put yourself out there.”

For much of the past decade, I tried to.

This is my last column for this newspaper. I am joining Jason Whitlock’s new Web site at ESPN intersecting sports, culture and race, to be launched sometime next year. I plan to continue the work my editors at The Post have generously supported, especially now that many of society’s most substantive conversations about race, class, money, power, cultural identity — a social-conscience renaissance — are suddenly mushrooming out of America’s locker rooms.

For the first time in my career, I won’t be working for a company anchored by a printed product. That sounds like nostalgic sap, especially to anyone reading this on a mobile app. But for the child of a longtime print man, who sat me on the typewriter keys of his Underwood in the offices of the San Jose Mercury News as an infant, it feels like the breaking of some familial bond I never imagined could be severed.

Maybe that hereditary pull toward idealism is why I never foresaw Arenas gouging out this town’s hope on one fateful, criminally mischievous day.

Despite all evidence to the contrary, in fact, I still believe giving up on Robert Griffin III too early would be a much bigger mistake than mortgaging all those draft picks to get him.

And I honestly think Drew Storen can still get the last out that will bring a National League pennant to Southeast Washington.

My heart gets in the way of my head sometimes. Guilty as charged.

In an increasingly snarkier era of #hashtagthis and Instagramthat, idealism can still free us from social media’s spawn: uncivil discourse and polarity. Twenty years of writing at two of the nation’s greatest newspapers and the necessary, if awkward, advent of the digital age have not dampened the mission: Good writing born of great reporting is still the lifeblood of journalism. The best of it requires time for deliberation and thought, which neither we nor our readers have in sufficient quantities anymore.

Still, in the moments we stop to celebrate rather than merely calibrate the games and the people who play them, the best of human majesty emerges. Even now I can still conjure:

● Lamar Butler smiling forever after George Mason shocked No. 1 Connecticut, sending the original mid-major Cinderella to the Final Four.

● Joe Gibbs summoning his players’ desire from another era in the wake of Sean Taylor’s tragic death — and that team surreally winning its final four games to make the playoffs.

● Jayson Werth’s walk-off laser over the left field wall to force Game 5.

● Griffin high-stepping down that sideline in 2012, braids bobbing beautifully out the back of his helmet, before it all went bad.

● Gilbert, rising and firing at the buzzer in Chicago, in 2005.

● Marissa Coleman taking over an NCAA women’s regional in a half-filled arena in Raleigh, not enough people in the world realizing she had just transported Maryland like Michael used to transport the Bulls.

● And, of course, Gary Williams and Greivis Vasquez, guns blazing, going out in glory or up in flames — no middle ground.

That 2010 Maryland men’s basketball team is the one scab that won’t heal. When their comeback against Michigan State ended with a cruel buzzer-beater in the second round of the NCAA tournament, I knew all those kids except Greivis would never play a bigger game in their lives.

Given all the crestfallen losses, all the promise that plummeted, it’s probably best the games didn’t fascinate me as much as peeling back the layers of the people who played them.

Covering a LeBron Finals or a Usain Bolt Olympiad was a privilege, a pure adrenaline rush. But I would still take crying with Dexter Manley over the addiction that made him pawn his Super Bowl ring and the good man who got it back for him. I would take the last-place finisher in a 100-meter qualifying heat over the world record holder if I know Tahmina Kohistani had to survive the Taliban to get to that finish line in London.

The past few weeks, I have thought long and hard about what I really want to end with. The only two words that come to mind: Thank you.

Thank you for playing whatever part you did in the best job I’ve ever had. I made my bones writing about the NBA at the New York Times, but this is where I recognized my voice, what I believe, who I am.

To the people who play the games, who let me into their lives and were vulnerable enough to tell me who they really are, I have only gratitude and the hope that I portrayed you honestly and fairly.

Thank you for letting me share pieces of my own life — some harrowing, others hopeful, all probably too sentimental and gooey for the “Stick-To-The-Damn-Games” crowd.

Thank you for often putting up with someone who at times probably needed to block himself on Twitter.

You didn’t have to agree with me always — or ever. But if you took the journey anyway, I’m grateful to have had you.

In 2004, joining a murderer’s row columnist lineup was intimidating. No one could write like Boz, be as funny and subversive as Kornheiser, as connected and incisive as Wilbon or as fearless and gifted as Sally — just as they could never be Shirley Povich, start date 1923.

You don’t aim to be a “star sports columnist” at The Post as much as you hope not to screw up a 91-year tradition of crackling commentary.

I hope I haven’t. In 11 of my most memorable years, it has been humbling just to be on the lineup card.