John Newlin formed a partnership with his sons, James and Johnathan, in 1844, for the production of yarn. Later, they expanded into weaving and dying.  A cousin of the sons, George Guthrie, was added to the partnership after the elder, John Newlin's, death.

John Newlin, the abolitionist, joined the Manumission Society of North Carolina, and served as their lobbyist duinrg General Assembly session.

John and Rebecca Long Newlin had ten children: James, Oliver, Jonathan, Cyrus, William, Mary Ann, Deborah, Thomas, Gulielma and Nancy. He was 91 when he died.