GL Hearn was established at London Bridge as a private practice in 1923 and by 1961 the then GL Hearn & Partners had expanded with three other offices in England and one in Scotland. In 1985 GL Hearn moved to larger London Headquarters to accommodate the growth of Planning, Valuation and Landlord and Tenant work.

In 1998 a new corporate identity was launched and the company achieved ISO 9001 registration, becoming incorporated as a private limited company the next year. In 2004 the Warrington office relocated to Manchester and, after 81 years based in South East London, the Headquarters moved to 20 Soho Square, London W1.

GL Hearn today is a successful multi-skilled property consultancy with a nationwide network of offices in London, Manchester, Glasgow, Bath, Sunderland and Southampton.