Watson was first elected to the Tennessee House of Representatives in special election in January 2006 to replace Chris Newton, who resigned as part of Operation Tennessee Waltz. He was re-elected four times. He was an at-large representative at the 2008 Republican National Convention. In 2010, he received the Legislator of the Year by the County Officials Association of Tennessee. In November 2011, Speaker Beth Harwell appointed him to the Tennessee Criminal Justice Coordinating Council. On October 5, 2013, he announced his intentions to run for sheriff of Bradley County. He was elected in 2014, defeating incumbent Jim Ruth, and resigned from the Tennessee House the following August, upon taking office. In 2018, he ran for reelection, and lost to challenger Steve Lawson by 1,175 votes. He was succeeded by Lawson in September 2018.