Assisted his brother James Catlin and sister-in-law Dr. Martha van Rensselaer in hiding runaway slaves while at Allegheny College in Meadville. Henry Catlin then came to Erie in the early 1850s and began publishing the pro-abolition The True American from 1853-1861. He often hid fugitive slaves in bins of his paper while they awaited Hamilton Waters, who helped them continue their escape to freedom. Catlin was threatened with his life when he brought Frederick Douglass to speak at Park Hall in 1858.