Lance Hewitt came from a rural, grazing background. He was the son on Robert and Frances Hewitt, of Singleton. He was educated at Maitland High School. Most of his undergraduate years were spent as a resident of Wesley College, where he took an active part in College activities, participating in cricket, football and athletics. He was senior student in 1930. After serving as RMO at Sydney Hospital he entered general practice for a short time in the Singleton area, then moved to the Enmore-Newtown area for many years. He was appointed Clinical Assistant in Medicine to the Royal Prince Alfred Hospital from 1940 to 1957 and was a tutor in medicine at the University of Sydney during the years of World War II from 1941 to 1944. He was tutor in medicine at St. Andrew's College from 1942 to 1944 and to Wesley College from 1942 to 1950. He was admitted to Membership of the Royal Australasian College of Physicians in 1941, and made a Fellow in 1973.

He moved to Macquarie Street and practiced as a consultant physician until his retirement in 1967. During this time he worked as Fellow in Allergy at the Community Hospital and developed a special interest in diabetes and collaborated with Keith Harrison and John Cobley in a clinical investigation of anti-diabetic drugs. He also served as Chief Medical Referee for the Government Insurance Office. He served in the rank of Captain in the AAMC from 1931 to 1935.

He married Rene Mary Patrick in 1930 and is survived by three daughters. He spent the years of his retirement at Clareville where he maintained his interest in outdoor activities such as golf and sailing. Lance was a conscientious practitioner and a quiet achiever. He had a pleasant and friendly manner which was evident already as a student and which ensured success in his professional life.