[4] As the head of NBCUniversal's advertising sales, she led a department of over 2,000 people, and played a key role in the launch of the Peacock streaming service.

[4] Though praised by advertisers and acknowledged as a hardworking saleswoman, associates from her time at NBCUniversal said her tenure was "marked by instability," with multiple reorganizations creating a decline in the culture of the department.

Yaccarino assumed the position of chair of the Ad Council's board of directors in January 2021, for a term that ran until June 30, 2022.

[15] Following Elon Musk's acquisition, Yaccarino pledged to him that NBCUniversal4 would continue advertising on the social network, according to people familiar with conversations.

[17][18] Upon her appointment, the Financial Times noted that Yaccarino's previous work with the World Economic Forum (WEF) had earned backlash from some "more conspiracy-minded Musk fans" who distrusted international political organizations.

Musk, a harsh critic of the WEF, stated that Yaccarino's links to the organization would not harm his self-proclaimed commitment to free speech on Twitter.

[4] After being ignored, the CCDH published its research showing the rise of hate speech and misinformation; Yaccarino suggested to Musk that Twitter sue, which it did that July.

[4] In November, after Musk made comments in support of an antisemitic conspiracy theory, a number of companies, including Yaccarino's former employer, Comcast, paused their advertising with X.

"[29] At a company meeting, when asked what she would like the outcome of the lawsuit to be, Yaccarino replied, "the validation that Media Matters, unfortunately, manipulates, in this case, not just advertisers, but people in general.

"[30] Fortune listed Yaccarino as one of the CEOs who struggled the most in 2023, writing that she "seems either unable or unwilling to restrain her boss from his worst impulses while failing to reassure advertisers that all is under control.