“He is not positioned as an icon,” a Verizon spokeswoman said at the time. “His role is to give visibility to the real people in the company who test the network.”

Mr. Marcarelli made dozens of commercials with Verizon. His relationship with the company formally ended in 2012, he said, though in the fall of 2010, he was told that Verizon would be taking a new direction in its advertising.

A 2011 profile in The Atlantic made it seem as if he were glad to leave the job behind. But Mr. Marcarelli said that was not the case.

“We all set out to build and direct a career for ourselves, and I think the career shapes itself, sometimes in spite of our best efforts,” he said. “We come to acknowledge the gifts inherent in that, as well as the drawbacks.”

This spring he was approached by Sprint, which asked if he would like to try its service. It was understood that a role in an ad campaign was in the works. Mr. Marcarelli tried the service and, as he says in the commercial, liked it enough to switch from Verizon (and to receive what is, no doubt, a lucrative contract). He would not discuss financial details but joked, “This is not my volunteer job.”

He expressed gratitude that Sprint was letting him play himself, describing a “pretty amazing conversation” that he had with some Sprint employees after having already switched his carrier.

“I happened to mention to them that my husband has always been with Sprint,” he said. “And I asked them: ‘Incidentally, do you have any discomfort about the fact that I’m married to a dude? Is that going to be an issue? If it is, that’s kind of a deal-breaker for me.’