He was educated at Eton College and Cambridge University.
He has been particularly concerned in developing contemporary African art From 1957 to 1966 he was employed by the Anglo American Corporation in Johannesburg and Lusaka. While in Johannesburg he helped run Union Artists, a black theatre group that played to mixed audiences in apartheid South Africa.
In 1959 he founded the African Arts Trust, which supports black artists from South Africa.
When he returned to London, Loder became treasurer of the Institute of Contemporary Arts and later its chairman in the 1970s. From 1968 he was a Trustee and for 10 years chair of the Mental Health Foundation, for which service he was awarded the Commander of the Order of the British Empire. With the backing of Lord Rothschild, he built up a business with 2,000 employees in 30 countries.
In 1982, he became executive chairman of the literary agency Curtis Brown. In 1980, Loder met Anthony Caro who was trying to organise an exhibition of British abstract art in South African townships.
In 1981, when staying in New York State, the pair developed the idea of running workshops for professional artists, which became the Triangle Arts Trust.
They held the first Triangle workshop in 1982 for thirty sculptors and painters from United States of America, the United Kingdom and Canada at Pine Plains, New New York The workshops became an annual event, and Loder later helped organise similar workshops in South Africa, Zimbabwe, Botswana, Mozambique, Zambia, Jamaica and Namibia. From 1990 he ran a workshop at Shave Farm in Somerset.