In 1854, Dr. Wentworth left his position to spearhead a Methodist Mission to Foochow, China, along with some students who were just graduating from Dickinson, including Otis T. Gibson. In 1862, he had to cut short his work in China because of the state of his wife's health. The couple returned to Troy Conference where he then worked as a pastor.
Wentworth was editor of the Ladies' Repository from 1872–76, after which he was semi-retired, writing and serving on committees for the Methodist Church. On May 26, 1886, he died at his home in Hudson Falls, New York.
The son of Erastus and Esther (States) Wentworth, and seventh generation descendant of William Wentworth (elder), Erastus married three times, was widowed twice, and had twelve children, one in China.