Wall was first elected to the Legislative Assembly of Saskatchewan as the Member for Swift Current in 1999, and he was re-elected four times, in 2003, 2007, 2011, and 2016. He became leader of the Official Opposition Saskatchewan Party on July 15, 2004, replacing Elwin Hermanson, and he led the party to a majority government in the 2007 election. In the 2011 election, Wall's government won the largest vote share in Saskatchewan's history with 64% of the popular vote and 49 of the 58 seats in the legislature. The 2016 election delivered Wall another majority, marking the first time since 1925 that a party other than the New Democratic Party or its predecessor, the Co-operative Commonwealth Federation, had won three consecutive majority mandates.