In 2005, Peltz, May, and Ed Garden, founded Trian Fund Management, L.P. As an activist investing firm, Trian has invested in such companies as Heinz, Cadbury, Kraft Foods, Ingersoll Rand, Wendy's, DuPont, Mondelēz, PepsiCo, State Street Corporation, Procter & Gamble and Family Dollar.
In 2005, Peltz was among 53 entities that contributed the maximum of $250,000 to the second inauguration of President George W. Bush. He is also a contributor to Jewish causes. A 2020 supporter of Donald Trump. Peltz has sat on the Board of Trustees of New York-Presbyterian Hospital since 2019.