Millhouse ran for the LCL leadership pre-selection following leader Sir Thomas Playford's retirement, but lost to Steele Hall, another member of the LCL's progressive faction. Instead, following the LCL's return to power at the 1968 election, Millhouse was given the portfolios of Attorney-General, Aboriginal Affairs, Social Welfare, and Labour and Industry. In these roles, Millhouse gained a reputation as a crusader for progressive social change as he sought to position South Australia as a national leader on social issues. During 1969 Millhouse was the architect and the major proponent for abortion on health grounds in South Australia, a decision he would come to regret decades later, claiming it had become "abortion on demand". In the wake of the LCL's 1970 election loss, Millhouse was elected Deputy Leader of the Opposition on 2 June.