The Red Cross acquired Claremont House and the remaining 32 acres on title in November 1940. They were also interested in a property at Kingston but Lady Clark, wife of the Governor General and patron of the Red Cross, decided on Claremont House when she was taken by the wisteria growing over the front verandah.
The new Lady Clark Convalescent Hospital opened in 1941 after significant renovations and additions. The original chauffeur’s cottage barracked Italian prisoners of war who worked on the grounds of the hospital.
Approximately 2000 war veterans were patients at Lady Clark Convalescent Hospital between 1941 and 1947. After the war, the house became the Lady Clark Rehabilitation Hospital still operated by the Red Cross. It offered various rehabilitation services with workshops and occupational therapy units. The additions to the house during this period were extensive with the addition of a north wing, extension of the dining room, sub-division of many of the rooms for ward accommodation and the construction of many out-buildings at the rear of the site.
In 1951, the Royal Hobart Hospital took over the house and continued its operation. The Lady Clark Hospital continued to operate at Claremont until its’ functions were transferred to the purpose built, Douglas Parker Rehabilitation Centre in New Town in 1980.
The late 1960’s saw further division of the property, the formal gardens and tennis court in the north of the property were redeveloped for housing in association with the hospital. These small detached properties were later sold off to a private consortium and became The Lady Clark Centre for the elderly.
Claremont House became the site of Adult Education in 1980. Due to little government funding, the property began to deteriorate rapidly. The rear of the property was subdivided and Claremont Education Park, a secondary college opened in 1989. By the 1990’s the building was in crisis and the Claremont House Association was formed. It commissioned a conservation report from local Architect Michael Court and Landscape Architect Anne Cripps. Unemployed youth were engaged to address some of the urgent repairs.