Despite working in different mediums during his academic days, Zaheen choose to work in watercolors as a professional painter. He earned his diploma in 1974 and Rabia Zuberi appointed him as teacher straight away. Zaheen served Karachi School of Art for 25 years and remained with it as a dedicated teacher until the end. He was Head of Department of Fine Arts when he died in 2000.
Under the influence of Abdul Hafeez, Zaheen developed great interest in watercolor painting and eventually became one of the most eminent names among the Pakistani watercolor painters. He developed a unique style of his own and introduced abstraction in watercolor painting breaking the traditional landscapes. His work revealed a watercolorist of rare sensitivity, painting traditional aspects of Sindh in a wholly modern style.
He participated in twenty one group shows including the National Exhibition in 1980 and 1982. He won first prize in watercolor painting at S.S. Haider Award at Peshawar in 1983 and Best Painting Award at Sindh Artist Exhibition at Karachi in 1984.