He was member of the House of Representatives between 16 February 1972 and 11 September 1981. And once more from 16 September 1982 until 13 March 1983. Between his terms in the House of Representatives he served as State Secretary for Culture, Recreation and Social Work from 11 September 1981 until 29 May 1982. And as Minister with the same portfolio from that latter date until 4 November 1982 when he quit due to heart problems.
De Boer served as mayor of Haarlemmermeer between 1983 and 1986. He then became Secretary-General of the Ministry of Welfare, Public Health and Culture and served between 1986 and 1995. Until 1980 he was member of the Anti-Revolutionary Party, he then became member of the merger party Christian Democratic Appeal.