Dylan Baker (right) as Johnny Carson in 'I'm Dying Up Here'
CNN  — 

In exploring the colorful comedy scene of the early 1970s, the new Showtime series “I’m Dying Up Here” presents a keen reminder of Johnny Carson’s role – unparalleled before or since – in launching the careers of stand-up comics.

Carson moved “The Tonight Show” from New York to Los Angeles in 1972, and made a point of booking hot young comics. His approval was seen as the ultimate validation, and the difference between becoming a headliner and a one-way ticket back home.

Richard Belzer once called an “OK” sign from Carson at the end of a comic’s set as “a gesture from God.” The most coveted approbation, though, was being summoned over to the couch, an honor bestowed on only a handful of first-time performers.

In a New York Times piece after Carson’s death in 2005, comic Jeff Cesario quipped that some comics studied Carson’s reactions “like they were poring over the Zapruder film.”

“My whole life changed,” said Tom Dreesen, a veteran comic who toured with Frank Sinatra and is serving as a consultant on “I’m Dying Up Here,” regarding the “euphoric feeling” of his first appearance. “There’s no describing that first ‘Tonight Show.’ You knew that one appearance could not only make your career but break your career.”

Carson was widely credited with helping establish comics like David Letterman, Jerry Seinfeld, Garry Shandling and Roseanne. Freddie Prinze, famously, became the first comic invited to the couch in his 1973 debut – and landed a sitcom deal almost immediately afterward for “Chico and the Man.”

“I can’t actually compare it to anything else,” said Michael Aguilar, an executive producer on “I’m Dying Up Here” along with production partner Jim Carrey. “You hear the word ‘anoint’ a lot. … If you get the couch the first time, you’re going to be a star.”

The producers cast Dylan Baker as Carson, who appears sparingly but casts a long shadow. Aguilar likened his presence within the show’s fictionalized world to the Wizard of Oz – to the comics, a mysterious figure that wields enormous power.

Tom Dreesen attends the premiere of 'I'm Dying Up Here' at DGA Theater on May 31, 2017 in Los Angeles, California.

Dreesen recalled being bumped three times before finally getting his shot. The pressure was enormous, not only because of its impact on careers, he said, but because any comic realized that practically everyone they knew would likely be tuning in.

Various factors contributed to Carson’s outsized role, including the fact that the TV marketplace was much less fragmented during his heyday. Another facet is that unlike late-night hosts that followed him – Letterman and Jay Leno foremost among them – Carson wasn’t a stand-up comic by trade and harbored no insecurities about showcasing their talents.

“Johnny wanted comedians to score,” Dreesen said, adding that the main demand he placed upon his bookers – and a point made in the show – was “Don’t bring them here till they’re ready.”

Those who earned Carson’s praise represented a who’s who of the comedy fraternity, including Drew Carey, one of those called over to the couch. “The very next day,” Carey said in a 1996 interview, “I was in show business.”

“I’m Dying Up Here” premieres June 4 at 10 p.m. on Showtime.