Ms Yaccarino had been in talks for the job before NBC announced her departure today.
Former NBCUniversal advertising chief Linda Yaccarino will become Twitter's new CEO, current chief executive Elon Musk said on Friday in a tweet.
"I am excited to welcome Linda Yaccarino as the new CEO of Twitter!" Musk said. "@LindaYacc will focus primarily on business operations, while I focus on product design & new technology."
Yaccarino modernized the Comcast Corp entertainment and media division's advertising business and had been in talks for the job before NBC announced her departure Friday morning.
Since Musk acquired Twitter in October, advertisers have fled the platform, worried that their ads could appear next to inappropriate content after the company lost nearly 80% of staff. Musk earlier this year acknowledged that Twitter suffered a massive decline in ad revenue.
Twitter's "trajectory will immediately take a 180-degree turn" under her leadership, said Lou Paskalis, a long-time ad industry executive and CEO of AJL Advisory, a marketing consultancy.
Musk axed thousands of employees, rushed the launch of a subscription product that allowed scammers to impersonate major brands and suspended users with whom he disagreed.
"I think (Yaccarino) has climbed every mountain she could at NBCU and did it impeccably well. And there's no greater challenge than restoring order at Twitter," he said.
Yaccarino could not be reached for comment.
Her exit is another big blow to NBCUniversal. Last month, NBC parent Comcast said NBCUniversal CEO Jeff Shell was leaving after acknowledging an inappropriate relationship with a woman in the company, following a complaint that prompted an investigation.
Advertising President Mark Marshall will step in as interim chairman of NBCUniversal's advertising and partnerships group. Marshall was named president of ad sales and partnerships in 2018, overseeing NBC's broadcast entertainment, sports and advanced advertising sales.
Yaccarino's exit comes at a difficult time for NBCUniversal, which is preparing for its annual upfront presentation to advertisers on Monday at Radio City Music Hall.
Yaccarino joined NBCU in 2011, after 15 years at Turner Entertainment, and has been credited with taking the network's ad sales operation into the digital era.
As broadcast television audiences migrated to streaming, she took to the stage at Radio City Music Hall last year to tell advertisers their brand messages were not an afterthought. She said NBCUniversal incorporated ads in its Peacock streaming service from the outset.
"Twitter needs credibility with the advertising community," said Greg Kahn, chief executive of GK Digital Ventures media consultancy. "Linda has demonstrated her trust, her innovative nature of bringing new partners to the table and a deep bench of relationships."
Musk, the CEO of electric vehicle maker Tesla, completed his purchase of Twitter in October for $44 billion. He said in December that he would step aside as CEO once he found "someone foolish enough to take the job."
On Thursday, Musk tweeted that he had found a CEO without naming Yaccarino. One person close to Yaccarino said Musk's tweet may well have accelerated the timetable for her to join Twitter, which would be a balm to Tesla shareholders.
Shares of Tesla were down 1.3% on Friday, as analysts commented that a CEO hire would allow Musk to concentrate on the EV business. Comcast shares were little changed.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)
