Maxwell Carter's ability to support a range of organisations came through the success of the family business Austral Steel. He was involved in the Roy Carter Foundation, named after his father and Austral Steel's founder, which supported Legacy, Crippled Children's Association, Helping Hand Inc, and helped to establish Westminster School.
Since 1966 Maxwell's most significant commitment has been to the Art Gallery of South Australia through the donation of items for the M.J.M. Carter Collection of nineteenth century art, including the works of S.T. Gill, Arthur Streeton, Charles Conder, Frederick McCubbin and Tom Roberts. He has also presented items of Chinese blue and white porcelain and Japanese ivories.
In 1968 he began 18 years service (over two periods) on the gallery's board, followed by a position on the council of the Art Gallery of South Australia Foundation. Maxwell Carter was made an Officer of the Order of Australia (AO) for his commitment to the arts, particularly through the Art Gallery of South Australia, in 1985. The M.J.M. Carter Gallery was named in his honour.