In April 1965, William Fitzsimmons, MP for Belfast, Duncairn, was appointed to a Cabinet position, becoming Minister of Education. He moved to become Minister of Development in 1966, back to Education in 1968 and finally served as Minister of Health and Social Services from 1969 until the Parliament was prorogued in 1972.
In 1968, Fitzsimmons' daughter married a Roman Catholic. As a result, he resigned from the Orange Order. At the 1969 election, former independent Unionist Member of Parliament Norman Porter stood against Fitzsimmons as a candidate whose opposition to Catholicism was in no doubt, but Fitzsimmons held his seat.