Jay Cassidy began his career as a film editor in the 1970s working on documentaries and political advertisements. Over the course of his professional career, Cassidy has edited more than 30 films. He has collaborated with Sean Penn on all the films he's directed, most notably Into The Wild (2007) for which Cassidy was nominated for an Academy Award for Film Editing. Other credits include An Inconvenient Truth (2006), which won the Academy Award for Best Documentary in 2007, Brothers (2009), Conviction (2010) and Waiting for Superman (2010). Cassidy was nominated in 2012 for his second Academy Award for Film Editing for Silver Linings Playbook, directed by David O. Russell.
While a student at UM, Cassidy was a photographer for the Daily, 1967-1970 and photo editor during the winter 1970 semester. His photography during this period captured subjects as diverse as the 1968 presidential campaign, a 1967 homecoming concert featuring the Doors, and scenes of anti-Vietnam War demonstrations in Ann Arbor. His off campus photography covered events such as the 1968 Democratic National Convention in Chicago, the 1969 March on Washington, Richard Nixon's inauguration, the 1968 campaigns of Robert F. Kennedy and George Wallace for President and the 1969 Ann Arbor Blues Festival. Cassidy was also a photographer for the campus yearbook Michiganensian, 1967-1968.
Cassidy is a member of the Academy of Motion Picture Arts and Sciences and American Cinema Editors.