After graduating from Penn State, she worked at Turner Entertainment for 15 years before joining NBCUniversal, where she oversaw roughly 2,000 people, and was involved with the launch of its streaming service.
She has also built relationships in new media with the likes of Apple News, Snapchat and YouTube.
A 2005 profile in an industry publication portrayed her as a busy, married mother-of-two children, then aged 13 and 9.
“I have absolutely no hobbies,” she said at the time.
Business Insider’s Claire Atkinson has followed Ms Yaccarino’s career for two decades and said her background in advertising could help Twitter, which has seen its ad sales drop sharply since Mr Musk’s takeover.