Rosengart brings a lot of star power to the Spears conservatorship. Rosengart was recently featured in Variety's 2021 "Legal Impact Report," where he is mentioned that he represents Steven Spielberg, his Amblin Entertainment, Julia Louis-Dreyfus, Keanu Reeves, actor Sean Penn, and his non-profit aid group CORE. He also represents Eddie Vedder, the talent and sports agency Creative Artists Agency. Other clients include Shark Tank's DaymondJohn, actor Winona Ryder, and Jimmy Butler, a Miami Heat basketball player. He was also named to The Hollywood Reporter's annual list of "power lawyers", including 2021.
Rosengart argued Wednesday that it wasn't appropriate to create a conservatorship over Spears. He also addressed the pop star's dad, Jamie Spears. For the past 13 years, he has held primarily the conservatorship.