Peter Shack was elected to the House of Representatives for Tangney, Western Australia in 1977 and 1980, representing the Liberal Party.
He was defeated in 1983. Peter Shack was re-elected for Tangney in 1984, 1987 and 1990.
 
Peter Shack's Parliamentary Party positions have included:

Member, Opposition Shadow Ministry from 14 December 1984 to 11 April 1990; Spokesman on Employment and Industrial Relations and on Youth Affairs from 14 December 1984 to 9 September 1985; on Education and Youth Affairs from 9 September to 14 August 1987; on Employment, Training and Youth Affairs from 14 August 1987 to 16 September 1988 and on Health from 16 September 1988 to 11 April 1990.
 
Mr Shack did not seek re-election as Member for Tangney in the March 1993 election and officially ceased to be an MP with the dissolution of the House of Representatives on 8 February 1993.