Fleischer first came to international attention when, while serving his first of five years as Assistant, then Associate conductor of the National Symphony Orchestra, he conducted Dvorak’s Cello Concerto with Mstislav Rostropovich as soloist during the NSO’s 1990 tour of Japan and the U.S.S.R.
In 1995 Fleischer made his debut with New York City Opera conducting “The Magic Flute.” Fleischer’s operatic repertoire included productions of La Bohème, Turandot, Tosca, Madama Butterfly, Don Giovanni, La Traviata, and others.
Active as a composer, Fleischer was a national leader in the area of symphonic rock and world music fusion.
Pioneering these new and growing genres, he worked with artists such as John Densmore (The Doors), Natalie Merchant, Blondie, Ani DiFranco, John Cale (Velvet Underground), Garth Hudson (The Band), Kenny Rogers, and Native American artists R. Carlos Nakai, Burning Sky, The Hawk Project, The Benally Family, and others.
As an advocate of new music, Fleischer commissioned and conducted world premieres and works by living composers.