To set the scene, the year was 2005, and Domingo was in Berkeley, Calif. He started the story saying he was just “minding your business going into a Walgreens” when a complete stranger caught his eye.

Colman Domingo didn’t take home an Oscar on Sunday, but the “Sing Sing” actor with deep Bay Area roots made waves online for much more adorable reasons. During a commercial break, he hopped onstage ...