In Israel, Seelig was a pionner in the new peofession of interior design and became one of the country's most prominent designers. His work ranged from private homes to large hotels and public institutions throughout the country.
After retiring from his practice in 1974, Heinz Seelig began painting on a full-time basis. What had been a hobby throughout the busy years if his architectural practice became an enjoyable and successful second career. He soon had his first one-man show in Vancouver, Canada (1975) and won the second prize in the important International Competition for Native Art held by the Galerie Pro Arte Kasper in Switzerland.
During his last ten years, Seeling was among the most prolific artists in Israel. His major shows include the Goldman Art Gallery in Haifa; the Israel Art Festival in Ottawa, Canada; Kawede Gallery, Berlin; Art Expo, New York; the New Gallery, Haifa; the Ida Kinche Gallery, Tel Aviv; a traveling exhibition in six museums in South Africa; Paperworks Gallery, Vancouver, Canada; the North Shore Congregation, Chicago and the National Museum of New Zealand.
Seelig is particularly well-known for his more than 40 lithographs, includins three series of the Book of Esther; the Story of Paradise and the seven days of Creation. Sets of the later series are in the collections of President Jimmy Carter and the late President Sadat. An award-winning calendar of Seelig's work was published by Multnomah Press. In the same year, he was commissioned to design two stainted glass windows ten feet in diameter for the North Shore Congregation in Chicago.