Lowenstern holds a B.M. and Performer's Certificate from the Eastman School of Music, an Artist's Certificate from the Sweelinck Conservatorium Amsterdam, and an M.M. and D.M.A. from the State University of New York at Stony Brook. In 1989, Lowenstern received a Fulbright grant to study in Amsterdam with bass clarinet virtuoso Harry Sparnaay. In addition to Sparnaay, Lowenstern's clarinet and bass clarinet teachers have included Charles Neidich, Richard MacDowell, and John Bruce Yeh, and he has also studied composition with Daniel Weymouth.
Lowenstern is based in Brooklyn, New York. In his early years, he performed in various ensembles representing a wide range of musical genres, including The Chamber Music Society of Lincoln Center, Steve Reich and Musicians, the Orpheus Chamber Orchestra, The Klezmatics, Robin Cox Ensemble, John Zorn, and Billband. In 1991 he won the second prize at the International Gaudeamus Competition in Rotterdam, Netherlands.
Lowenstern has created numerous compositions for bass clarinet, both solo and with electronics. His works explore the possibilities of large ensembles of bass clarinets (done by multi-tracking), as well as juxtaposing the instrument with drum and bass-style beats more common to electronic dance music than to contemporary classical music. He has also composed music for film, dance and advertising. Since October 2006, a segment of his playing with Billband has been used as the theme for the National Public Radio segment "Science Out of the Box," which airs on the Weekend All Things Considered program.
Lowenstern has served on the faculties of New York University and the Juilliard School, and is now on the faculty of the Manhattan School of Music, teaching bass clarinet in their Contemporary Performance Program. He served as bass clarinetist of the New Jersey Symphony Orchestra from 1999 until his retirement from orchestral playing in 2005. He appears on over fifty CDs, including six solo recordings. The album Ten Children garnered Lowenstern a "Parenting Pick" award in Parenting magazine's music listing for 2004.
In 2009, Lowenstern took part in the In C Remixed project which featured remixes of the seminal Terry Riley work "In C" by 16 artists including Meat Beat Manifesto's Jack Dangers, DJ Spooky, David Lang, Radiolab's Jad Abumrad and many others.