Cohen, who has so far had a two-decade career as a musical director, and who has significantly developed every organisation with which he has been involved, studied conducting with Gustave Meier and Paul Vermel.
At the time, he was living in Hawaii, and held the position of music director of the Kumu Kahua Theatre Group, which specialised in locally-themed productions.
He composed music for numerous theatre productions, including ones based on the life of Princess Ka'iulani and the Aristophanes farce Ecclesiazusae (translated as either "Women in Parliament" or "The Congresswomen").
Cohen spent the 1991–1992 season in England in creating a self-study program by attending rehearsals at English National Opera and asking a lot of questions of Mark Elder, who was the music director.
During the late 1990s and early years of the 21st century, Cohen played a significant role in the resurgence of interest in the British composer Richard Arnell by conducting several of his symphonies in concert and by recording all of them for imminent commercial release.