Hersch was born in Washington, D.C., on June 25, 1971, and grew up in suburban Reston, Virginia. He took up the piano early, but he became interested in classical music, specifically, only at age 18 when he saw a video recording of Georg Solti conducting Beethoven. Hersch attended the Peabody Conservatory in Baltimore and enjoyed a stint at the Moscow Conservatory in 1995, studying there with Albert Leman and Roman Ledenev and earning a composition certificate. He returned to Peabody, earning a graduate degree and eventually joining the school's composition faculty. He amassed an unusually large number of prestigious awards, including the American Composers Prize (1997), which led to his orchestral work Elegy being performed at Lincoln Center by conductor Marin Alsop, and the Rome Prize (2000). Hersch also benefited from studies with John Corigliano, George Rochberg, and John Harbison.
Hersch's compositional career began while he was still a student, with such works as the Sonata No. 1 for unaccompanied cello (1994). His output includes orchestral works, concertante pieces, opera, chamber music, vocal music, choral music, and an unusually large group of works for a solo instrument. His Symphony No. 1 appeared in 1998, and in 2000, his Symphony No. 2 was completed in response to a commission from conductor Mariss Jansons and the Pittsburgh Symphony Orchestra. Hersch increasingly often performed his own keyboard compositions, including the massive The Vanishing Pavilions, which he recorded for the Vanguard label on a 2007 double CD set. In 2010, he issued the piano concerto Along the Ravines.
Hersch turned to opera in 2014 with On the Threshold of Winter, which dealt with terminal illness and was inspired by the death of one of the composer's close friends. He has collaborated with a variety of top-notch international instrumentalists specializing in contemporary music, including violinist Patricia Kopatchinskaja, who premiered his Violin Concerto in 2015, violinist Miranda Cuckson, the Orpheus Chamber Orchestra, and Ensemble Klang. By 2022, when Hersch's The Script of Storms appeared on an album by the latter group, more than 25 of Hersch's compositions had been recorded on such labels as Naxos, Cedille, and Musical Concepts in addition to Vanguard. ~ James Manheim, Rovi