As a composer, arranger and conductor, he has worked with such orchestras as the London Symphony, the Chicago Symphony, the Boston Pops, The New York Philharmonic, the Royal Philharmonic of London, and the Toronto Symphony. 

His Broadway theater credits include Porgy and Bess (London production by Trevor Nunn), Sinatra At The Palladium, Sweet Charity, Kiss Me Kate (2000 Tony Award), Bells Are Ringing, Flower Drum Song, Parade, The Life, Cyrano, The Goodbye Girl, Will Rogers Follies,  and Sinatra At Radio City

Among his film credits are The Rosary Murders (starring Donald Sutherland), Hollow Image (starring Morgan Freeman), The Last of the Belles (starring Susan Sarandon), Let's Get Lost (starring Chet Baker “ Best Documentary at the Cannes Film Festival), The People Next Door (starring Eli Wallach and Julie Harris), Time Piece (Jim Henson Productions “ Academy Award nomination for Best Short Subject). 

For television, Sebesky's work has included Allegra's Window on Nickelodeon (Emmy nomination), The Edge of Night on ABC (Emmy nomination), and Guiding Light on CBS (Emmy nomination). 

As a recording artist, Sebesky's work includes nine recordings under his own name, all of which were GRAMMY nominated.  Included are Giant Box, Rape of El Morro, Full Cycle, Moving Lines, Symphonic Sondheim, I Remember Bill (1999 GRAMMY Award), and Joyful Noise (winner of two GRAMMY Awards in 2000).

Sebesky has also created the music for many well known commercials.  Among the companies he has represented are:  Corning (Clio Award), Hanes, Hallmark, Dodge Trucks, General Electric (Clio Award), Hershey's, Cheerios, Calvin Klein (Clio Award), Nike, Oil of Olay, Pepsi and Kodak. 

Sebesky is the author of the best selling orchestration text book, The Contemporary Arranger.