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.
Watson's political career began with a council seat in 1943 as an Alderman, and he served until 1945. Friends persuaded him to run for mayor in 1945, despite his belief that he would likely lose. To his surprise, Watson won the election and became Calgary's 25th Mayor in 1945, but was defeated by Donald Hugh Mackay in the 1950 municipal election.