Hyndman was an active member of the Progressive Conservative Party of Canada, and was set to participate in the 1959 party convention, however his work commitments required him to step away, Jim Edwards the alternate went in his place. Five other members of his party were elected that year. Together the six formed the official opposition. Due to redistribution in the
1971 general election, the electoral district of Edmonton West was abolished. Hyndman ran for re-election in the new electoral district of Edmonton-Glenora. He was re-elected to the legislature with a sizable majority. The Progressive Conservatives under the leadership of
Peter Lougheed formed government. Hyndman was appointed to the
Executive Council of Alberta shortly after the election as Minister of Education. Running for re-election as a cabinet minister in the
1975 general election, Hyndman slightly increased his popular vote. He won his district with a landslide as the opposition vote collapsed. Hyndman defeated future Member of the Legislative Assembly
Alex McEachern and two other candidates. Immediately following the election Hyndman was shuffled to become the Minister of Federal and Intergovernmental Affairs. He ran for his fourth term in office in the
1979 general election. Hyndman's popular vote waned slightly from the previous election. There was no significant strength in the opposition vote. He still won his district with a landslide majority. Lougheed appointed Hyndman as the new Provincial Treasurer following the election. In Hyndman's fifth election he reclaimed the votes he had lost in 1979. He won his final term in office in the
1982 general election easily defeating three other candidates. Hyndman held the Provincial Treasurer portfolio after
Don Getty became Premier in 1985. Hyndman retired from the legislature at dissolution in 1986. During his 19-year career in the Alberta Legislature, Hyndman served as the Minister of Education, Minister of Federal and Intergovernmental Affairs, Government House Leader, and Provincial Treasurer. ==Late life==