Mathew S. Rosengart

Mathew S. Rosengart is a former federal prosecutor who now practices as a media and entertainment litigator as a shareholder at Greenberg Traurig LLP.

He graduated cum laude from Boston College Law School, clerked for David Souter when Souter was on the New Hampshire Supreme Court and joined Greenberg in 2011. Variety called Rosengart "Hollywood's King of Litigators."

He is on the board of governors of the Beverly Hills Bar Association, which presented him with its Excellence in Advocacy Award following a warm introduction by Souter.

In 2021, Rosengart drew national media attention for his successful effort to extricate Britney Spears from her 13-year conservatorship. He has continued to represent her, defeating nine recent motions filed by lawyers for her father, her former conservator, that sought to take her deposition and engage in discovery of her financial records.

For his work on that case, Rosengart and colleagues won a 2022 CLAY Award from the Daily Journal. In re the Conservatorship of the Person and Estate of Britney Jean Spears, BP108870 (L.A. Super. Ct. filed Feb. 1, 2008).

In Spears' bestselling memoir, "The Woman in Me," she calls Rosengart "amazing" and added, "Once Matthew was in my corner, I felt that I was getting closer to the end."

"Very humbling and moving," Rosengart said. "You don't do the job for mentions in books, but it's appreciated."

Further fallout came when Gov. Gavin Newsom signed into law AB 1663, a conservatorship reform package unofficially known as the "Free Britney Spears Act."

Last year, Rosengart fought and prevailed for longtime client Sean Penn and his Community Organized Relief Effort (CORE) in a showdown with federal officials over the group's COVID-19 testing and vaccination program at Dodger Stadium.

After national media outlets praised the program, anonymous posters complained about working conditions -- including a lack of the right brand of donuts and lunch sandwiches -- provoking Penn to write a rebuttal. "He used some scathing language," Rosengart said, "and the National Labor Relations Board cherry-picked that to make a case that he was threatening workers under the labor laws."

After a year of fruitless settlement talks, the NLRB proposed a deal that Penn rejected. "I didn't get into this to be a sellout," he told Rosengart. "Let's go to trial."

"He is a dream client and he had a principle at stake," Rosengart said. Following an April 2023 hearing, an administrative law judge rejected the NLRB's claims of unfair labor practices and dismissed the case. Community Organized Relief Effort, 31-CA-272228 (NRLB, filed Feb. 3, 2021).

"It's rare that you get to actually get to go to trial and beat the government," Rosengart said. "The NLRB and its general counsel have broad power, but in this case, they clearly overstepped and abused that power, while also seeking to infringe upon Mr. Penn's First Amendment rights."

--John Roemer