Lofting was born in Maidenhead, England, to English and Irish parents. His early education was at Mount St Mary's College in Sheffield, after which he went to the United States in 1904, completing a degree in civil engineering at the Massachusetts Institute of Technology. He studied at London Polytechnic.He traveled widely as a civil engineer, in Canada, on the Lagos Railway, and Railways of Havana, Cuba. In 1912, he married Flora Small; they had two children.He enlisted in the Irish Guards to serve in World War I. Not wishing to write to his children of the brutality of the war, he wrote imaginative letters that were the foundation of the successful
Doctor Dolittle novels for children. Seriously wounded in the war, he moved with his family to Killingworth, Connecticut, in the United States, in 1917. He served in the British Ministry of War Information.His first wife died in 1927, and second wife in 1928. He married Josephine Fricker, in 1935; they had a son named Christopher, who was the executor of his literary estate.
For years it was a constant source of shock to me to find my writings amongst 'juveniles,'" Lofting reported. "It does not bother me any more now, but I still feel there should be a category of 'seniles' to offset the epithet.