 When the East Alabama College opened in 1859, he was appointed professor of natural science at that school, a position he held concurrently with his position at the Auburn Female College.Darby remained professor at Auburn until 1869, when he was elected president of Kentucky Wesleyan College in Millersburg, Kentucky.In 1875, he resigned that position and moved to [[New York City|New York], where he died in 1877.