Career
He was a chartered accountants He was elected Sheriff of the City of London for 1952 and Lord Mayor of London in 1958. He was president of the Baden-Powell House building committee of The Scout Association from 1953 until the building was finished in 1961.
As a tribute to his contributions, the Scout Association has created a Sir Harold Gillett Memorial Fund to help pay the expenses of special needs Scouts and members in need to visit London and stay at the Baden-Powell House hostel.
Gillett was created a baronet, of Bassishaw Ward in the City of London, in 1959.