Neidhardt was a painter and sculptor, who taught at Austin College in Sherman, Texas for 19 years, after which he held the position of professor emeritus of art for 23 years. Having been born in Chattanooga, he earned his B.A. from the University of Tennessee at Chattanooga, his M.F.A. at the university of Florida, and his Ph.D. from Ohio State University.

In 1953-54, the University of Florida announced that Neidhardt was awarded a Fulbright grant to the Rijksacadamie in Amsterdam. Neidhardt has had many solo exhibitions, and his paintings and sculptures are widely included in Texas museum collections.