Owing to his profile in the labour community, Watson was first elected to Calgary City Council in 1943 as an Alderman, and served through to 1945. Friends convinced Watson to contest the 1945 election, and he agreed to run conceding that he would most likely lose. To his surprise, Watson won the election and became the 25th Mayor of Calgary in 1945, and held that office for until he was defeated by Donald Hugh Mackay in the 1950 municipal election.
Due to his prominence in the labor movement, Watson was first elected as an Alderman on Calgary City Council in 1943 and served until 1945. Friends encouraged him to run for office again in 1945, and he agreed to do so, acknowledging that he would likely lose. To his astonishment, Watson won the election and became the 25th Mayor of Calgary in 1945, holding the position until he was defeated by Donald Hugh Mackay in the 1950 municipal election.