Joel Lazar has been acclaimed by the Washington Post as "…one of Washington's premier conductors of both old and new music…." He has conducted the Theater Chamber Players in engagements at the Kennedy Center, the Library of Congress, and on tour from 1986 to 2003. He has appeared as guest conductor with many orchestras and contemporary music ensembles in the Washington area, including a 20-year tenure as Music Director of the JCC Symphony Orchestra from 1988 until 2008. He has been Music Director of the Symphony of the Potomac since it was founded in 2008.

During the 1990s, he was Music Director of Alexandria-based Opera Americana, and was Principal Conductor for the In Series' opera productions from 1991 until 2011. He was a cover conductor for the National Symphony Orchestra from 1997 to 2001, sharing the stage with Music Director Leonard Slatkin in critically praised and enthusiastically received performances of Ives' Fourth Symphony in April 2001. Joel Lazar is also Music Director of the Washington Sinfonietta, with which he has been affiliated since 2007.

Music Director of the Tulsa Philharmonic from 1980 to 1983, Joel Lazar has also appeared with the orchestras of San Antonio, Louisville, Pasadena, Oklahoma City, Richmond, Harrisburg, Wheeling and Johnstown, with Sarah Caldwell's Opera Company of Boston, and was Music Director of the Richmond Philharmonic from 1990 to 1992. During a period of European residence he conducted the BBC Philharmonic, the Danish National Orchestra, the Tivoli Orchestra and the Scottish Baroque Ensemble in concerts, broadcasts and recordings. His performances and feature interviews have been broadcast by the BBC, Danmarks Radio, Bayerischer Rundfunk, WCLV-FM (Cleveland, Ohio) and National Public Radio.