When Prime Minister Patrick John was ousted from office in June 1979, Pierre Charles was among those who served in the interim government. At the time, he was also involved in the management of an agricultural trade organization, Farm to Market. In 1980, he ran for election on the left-wing Dominica Liberation Movement (DLM) ticket; he lost in that race to the candidate of the Dominican Freedom Party (the party led by Mary Eugenia Charles). By 1985, Pierre Charles had left the DLM to join the Dominica Labour Party (DLP), the traditional opposition party led by Roosevelt Douglas. Pierre Charles won his election contest in 1985, and when he became prime minister in October 2000, he had served longer in Parliament than any other member. When Roosevelt Douglas assumed the prime minister post in February 2000, Pierre Charles was appointed minister of communications and works; Charles became prime minister in October when Douglas's unexpected death stunned the nation.