Patrick Cassidy (born 1956) is an Irish orchestral, choral, and film score composer.
Cassidy was born in Claremorris, County Mayo, Ireland. He received a master's degree in Applied Mathematics from the University of Limerick in 1985, and supported his early compositional activities with a day job as a statistician.
He is best known for his narrative cantatas – works he has written for orchestra and choir based on Irish mythology. The Children of Lir, released in September 1993, remained at number one in the Irish classical charts for a full year. It was the first cantata written in the Irish language since the work of Paul McSwiney in the late 1800s. The BBC later produced an hour long documentary on the piece. Famine Remembrance, a commissioned piece to commemorate the 150th anniversary of the Irish Famine, was premiered in New York's St. Patrick's Cathedral in 1996. In June 2007, the piece was performed at the opening of Toronto's Ireland Park with the President of Ireland as special guest.
Other albums include Cruit (arrangements of 17th- and 18th-century Irish harp music with Cassidy as the soloist) and Deirdre of the Sorrows, another cantata in the Irish language, recorded with the London Symphony Orchestra and the Tallis Choir. In 2004, Immortal Memory was released; a collaboration between Cassidy and Lisa Gerrard.
Cassidy now lives in Los Angeles with his family, where in addition to his concert work he has scored and collaborated on films and documentaries. He is uncle to the singer Sibéal Ní Chasaide who sang his arrangement of Patrick Pearse's Mise Eire at the official government commemorations of the 1916 Rising.
Cassidy's song Proclamation was played at the inauguration of Joe Biden in Washington DC on January 20, 2021.