In November 2016, Sales won an internal election among state Senate Republicans to be the president of the Montana Senate in the 2017 election. His opponent was Senator Eric Moore of Miles City. Although the vote was by secret ballot, it was described as a close case. He assumed office in January 2017. Sales broke with tradition in January 2017 by deciding to not sit with the state House in the customary beginning-of-session joint sitting to hear speeches from members of Montana's congressional delegation, the chief justice of the Montana Supreme Court, the Montana Superintendent of Public Instruction, and a Native American leader. Sales' choice to break from tradition was publicly criticized by former State Senate president Jon Tester.