Born and raised in Pennsylvania, Horter was a self-trained artist. Originally a commercial artist at graphic design agency N.W. Ayer, Horter went on to teach at Philadelphia Museum School of Art and at Tyler School of Art. His work often depicts urban life, and in 1911 he released a collaborative book with Jerome Meyers and Joseph Pennell entitled " An Illustrated Handbook of the City." Special honors include a Silver Medal from the Panama Pacific Exposition in San Francisco, an Etching Prize at Art Institute of Chicago, and prizes at the National Print Exhibition of the Philadelphia Print Club. The Whitney Museum honored him with a retrospective exhibition in 1978.