 Robertson was elected to the position of mayor of Vancouver as part of the Vision Vancouver slate.Prior to that, he served as a Member of the Legislative Assembly for Vancouver-Fairview, as a member of the New Democratic Party of British Columbia, from 2005 until his resignation in 2008 to run for the mayoral position.On January 10, 2018, Robertson announced in a Facebook post that he would not seek reelection later that year.