When he returned to England on a painting holiday, Heseldin met Lily Paul, his future wife, in Newlyn. They were married in the village of Rocky Hill, near Princeton, New Jersey, where their daughter, Lamorna, was born in 1922.
After several years of little success in the USA, he brought the family back to Newlyn where he rented a studio and began to paint full-time. His metier was depticting Cornish street and harbour scenes in watercolour, and his compositions were often detailed studies, probably due to his architectural training. He exhibited at NAG.
In the 1950s he and Lily moved to St Austell to live with their daughter and son-in-law, and he became a member of the St Austell Art Society.