Andrew McCaskill slid into Marcus Dwayne Johnson’s Instagram direct messages in September 2019 with a flirty note, telling him that he looked really cute in a suit he was modeling. The message he finally got back six weeks later wasn’t quite as playful.

“I’m thinking he’s going to be like, ‘Hey, Big Papa,’” Mr. McCaskill said with a laugh.

Instead, “Marcus was like, ‘Hi Drew, I see you’ve recently made a career transition, and I have a current career scenario I’m navigating,’” he said.

Though the corporate speak they settled into just after wasn’t exactly a love language, Mr. McCaskill, then an independent diversity, equity and inclusion consultant in Harlem, felt a tug to pay it forward. “Sometimes, being Black and gay, you’re sort of like a double minority,” he said. “What I didn’t want to do was be the guy who didn’t help out another Black gay man who was having a career issue. Especially one who was younger.”

Mr. McCaskill, 46, told Mr. Johnson, 30, to send him his résumé. Minutes later, it was in his inbox. “I was at a crossroads,” Mr. Johnson said, about a potential move between corporate jobs in Atlanta, where he lived.

Mr. McCaskill’s skills as a workplace negotiator had preceded him. “I had been following his career online a little bit,” Mr. Johnson said. “I thought, he’s cute, he’s smart and he’s older than me. Maybe he has some experience he can share.”