Under President Trump, the White House news briefing — once a Sisyphean burden for rumpled reporters — became the hottest reality show in Washington, a star-making showcase for journalists where heated exchanges went viral and drove big ratings.

So what happens when the protagonist gets written off?

Like the departure of a popular actor from a sitcom, Sean Spicer’s resignation on Friday deprives the briefing of its central character (its hero or its villain, depending on the viewer) and spells the end of an unlikely cottage industry that sprung up around the man who might already be the most famous White House press secretary of modern times.

Mr. Spicer’s six-month tenure was a life-changing experience for the figures in his orbit, enhancing careers and fueling national exposure. The actress Melissa McCarthy earned an Emmy nomination for her instantly famous impression of Mr. Spicer on “Saturday Night Live.” April D. Ryan, a correspondent for American Urban Radio Networks, leapt to cable news stardom after clashing with Mr. Spicer in the briefing room.

The experience was transformative for Mr. Spicer, too. Before January, his name recognition did not stretch beyond Washington. On Friday, the news agency Reuters dispatched a camera crew to broadcast a livestream of his house.