Annie McEwen grew up in country Victoria, the daughter of John McLeod, a farmer in Tongala, Victoria. She was educated at Girton Church of England Girls' Grammar School in Bendigo, Victoria. She married John McEwen on 21 September 1921 at Ballavoca, Tongala. They had no children. McEwen was an experienced farmer and with her husband, developed the soldier settler property. They sold it and bought others to eventually hold 3000 acres (1200 ha), in the Stanhope region. They succeeded in circumstances where others had walked off their blocks.

Annie McEwen was active in her local community and particularly in women's organisations such as the Country Women's Association and in the Country Party. She spoke at women's meetings and was a key organiser in the Country Party during the early stages of her husband's political career. She drove thousands of miles through Victoria to political meetings while her husband worked on his speeches in the back seat of his car. He was elected to the Federal Parliament in 1934 as member for Echuca. He later held the seats of Indi from 1937-1949 and Murray from 1949-1971, when he retired from politics. He became leader of the Country Party in 1958.

When her husband, as Minister for Air from 1940, established the Women's Auxiliary Australian Airforce, Annie McEwen was one of the women who gained the use of a large Toorak home and named it WAAAF House. She was appointed as a Dame Commander of the Order of the British Empire on 1 January 1966, 'in recognition of many years of distinguished devotion to the public interest especially in country areas'.

She died on 10 February 1967, so was not alive to see her husband assume the prime ministership of Australia for three weeks after the disappearance of Harold Holt in December 1967.

Sources used to compile this entry: 'Wife of Deputy PM dies: life of service', The Age, 11 February 1967; Lloyd, C. J., 'McEwen, Sir John (1900-1980)', in Australian Dictionary of Biography Online, Australian National University, 2006, http://www.adb.online.anu.edu.au/biogs/A150245b.htm.