De has graduated from Government College of Arts, Kolkata in 1975. He has had several one man shows and group shows in every major metropolitan cities of India since 1976. Yet participation in Banga Sanskriti Sammelan, Calcutta Metropolitan Festival of Art, 1995 and Millennium Festival of Art in 2000 are some of the prestigious ones in his career. His most recent participation has been at the Singapore Art Festival, 2006.
Sunil De is essentially an abstract painter who sees non-figurative forms within figurative manifestations. It is like a sudden revelation where matter breaks into colours forming a visual music of sequences of warmth and coldness. All paintings of Sunil De are signed as Suneel.