Following his education, he became an apprentice civil engineer with Jacob Owen in Portsmouth. When Owen was made senior Engineer and Architect of the Irish Board of Works and moved to Dublin, Lanyon followed. In 1835 he married Owen's daughter, Elizabeth Helen. They had ten children, including Sir William Owen Lanyon, an army officer and colonial administrator. Charles Lanyon was county surveyor in Kildare briefly, before moving on to Antrim in 1836. He remained county surveyor of Antrim until 1860 when he resigned from the post to concentrate on private work and other interests.