But it was not enough.
Rivers, with Rosenberg acting as her manager, felt NBC was being stingy with pay and dragging its feet with a new contract.
So when Rupert Murdoch wooed her to start a talk show on his then-new Fox network, Rivers began taking secret meetings in hotel rooms.
"They were in shock when I left," she later said of NBC. "But they just weren't coming through."
Murdoch offered her a $15 million paycheck and a five-year guarantee, she later said.
But "The Late Show Starring Joan Rivers" was not a hit. Ratings drooped and station managers quickly soured on Rivers. Behind the scenes, Rivers tangled with Fox executives over creative control and other issues. She left in May 1987 and was replaced with a rotating cast of hosts, including Arsenio Hall. Rosenberg committed suicide later that summer.
Rivers' career sunk. But she wasted little time plotting a second act.
She tried a daytime talk show, "The Joan Rivers Show," which lasted five seasons in the early 1990s.
Then her daughter, by then trying to build her own career as an on-air personality, floated her mother's name to take over E!'s red carpet pre-show package.
The result was bracing for celebrities and their handlers, who were used to adulatory coverage and harmless questions.
Rivers zinged the stars for wearing clothes she deemed atrocious and didn't mind taking other potshots too. Of the habitually dour Tommy Lee Jones, Rivers said, "He makes Hitler look warm and funny."
Her harsh criticisms often got in her in trouble with some of Hollywood's biggest stars, like Jennifer Lawrence, who said Rivers' E! show "Fashion Police" teaches young people "that it's OK to point at people and call them ugly and call them fat."
But her success in her new role gave Rivers yet another reinvention. "The red carpet suddenly became the red carpet," she later said.
Still, she was not done. She appeared on NBC's "Celebrity Apprentice" in 2009. Competing alongside her daughter, Melissa, the elder Rivers beat out poker player Annie Duke and endeared herself to viewers with caustic barbs.
Her stint on the reality show was chronicled in "Joan Rivers: A Piece of Work," a documentary that premiered at the 2010 Sundance Film Festival to rave reviews. The film revealed a raw portrait of the comedienne as she discussed her anxiety over aging and staying culturally relevant.
In one scene, she pointed to an empty calendar and exclaimed: "I'll show you fear. That's fear."
She developed her own merchandise line for QVC, populated mostly by costume jewelry and demure blouses, and moved into her daughter's Pacific Palisades home to film a reality show about their roller coaster of a relationship; it ran four seasons on WEtv. In June 2014, she published her 12th book, "Diary of a Mad Diva," a satirical journal which quickly became a New York Times bestseller.
Meanwhile, in an effort to tap into a younger demographic, she started filming a Web series out of her bedroom in Melissa's home. Called "In Bed With Joan," the show found Rivers coaxing YouTube stars and comedians like Sarah Silverman and Kathy Griffin onto her mattress for a chat.
"At this age, to be wanted is a miracle," she said in an interview with the Times in 2014, the year she turned 81. "I'm never satisfied. I'm as driven now as I was when I was 8 years old and said, 'I want to be an actress' and sent my picture to MGM. Just as driven. Just as crazed. Just as worried."
But loneliness could still get to her.
"Age, it's the one mountain you can't overcome," she said in the 2010 documentary. "I have no one to say, 'Do you remember? ... ' And that is very difficult."