Loepp grew up in Wyoming, Texas, Iowa and Oklahoma. He began his art studies in 1972 at the Art Students Academy in Tulsa, Oklahoma, then moved to New York City in 1976 and studied at the Art Students League of New York; this was followed by a year of travel through Europe. He returned to New York, where he painted cityscapes, some from atop the World Trade Center, and began a career as a portrait painter. In 2001 he returned to Wyoming.
In 1994 Loepp painted a portrait of Supreme Court Chief Justice William Rehnquist for the United States Supreme Court. The painting was subsequently placed near Rehnquist's coffin when his body lay in state after his death in 2005; the New York Times described the painting as showing "the four gold stripes with which the chief justice decorated each sleeve of his judicial robe and depicts him with a slightly bemused expression".
In addition to the Supreme Court, Loepp's paintings are in the collections of the Museum of the City of New York, Stanford Law School, University of Chicago, and William and Flora Hewlett Foundation. He has exhibited at the Brooklyn Museum, the Nicolaysen Art Museum and the Dahl Arts Center in South Dakota.
- Gage Academy
- Nicolaysen Art Museum
- Instructors and Lecturers - Past and Present, Art Students League of New York
- Larson, Kay. Italian Fantasies, New York Facts, New York Magazine Nov 21, 1983.
- Portrait of William Rehnquist, OYEZ
- Obermayer, Herman. Rehnquist: A Personal Portrait of the Distinguished Chief Justice of the United States. Simon and Schuster, 2009
- Bush and First Lady Visit Rehnquist's Coffin at Court The New York Times, September 7, 2005