Top 100 Lawyers 2024

A former federal prosecutor, Mathew Rosengart now practices as a media and entertainment litigator as a shareholder at Greenberg Traurig LLP.

After law school, he clerked for Supreme Court Justice David Souter on the New Hampshire high court, before Souter's elevation to the nation's highest court. This experience marked an interesting and eventful year in Rosengart's early career.

"I just saw him in July at our annual reunion," Rosengart said. "We started our reunions year after year by hiking in New Hampshire's White Mountains, followed by drinks and dinner in Boston, and it has evolved since then. I always say that hiking with him in the presidential range is like hiking with a Founding Father."

One of Rosengart's recent notable cases was representing his longtime client, Sean Penn, and his charitable relief organization, CORE. The organization was sued by the United States government through the National Labor Relations Board. Community Organized Relief Effort, 31-CA-
272228 (NRLB, filed Feb. 3, 2021).

After a multi-year battle, the case went to trial, and Rosengart successfully moved for a directed verdict. The judge dismissed the case, vindicating both Penn and CORE.

"I believed the NLRB's case was ill-advised from the outset and exemplified overzealousness and federal overreach into protective First Amendment freedoms," Rosengart said. "Beating the U.S. government, especially at trial, is a rare feat, and for these reasons, the victory was especially rewarding. The only downside was that my next witness was going to be Sean Penn, who would have been a great witness, and a true 'star witness.'"

Another significant matter in Rosengart's career was the Britney Spears litigation. He played a crucial role in obtaining the court-ordered suspension of Spears' father as her conservator and restoring her freedom and civil liberties in 2021. Re: the Conservatorship of the Person and Estate of Britney Jean Spears, BP108870 (L.A. Super. Ct. filed Feb. 1, 2008). Despite the protracted and complex probate court proceedings, Rosengart managed to extricate Spears from these entanglements. Throughout the process, he successfully defended against more than 10 motions filed by Spears' father, including efforts to take her deposition, which were ultimately unsuccessful at both the trial and appellate levels.

"Winning those motions and continuing to help and protect Britney, was extremely rewarding," Rosengart said. "As a result of our work together -- and Britney gets the credit -- she shined a light on the system, and among other things, the governor signed a bill changing the law to help protect against abuses and to ensure that conservatees in the future have the right to their own private counsel of their own choice."