Davidson moved to East York in 1947 after the death of her mother. Shortly after moving she was diagnosed with cancer at Princess Margaret Hospital. Feeling that she had not much time left Davidson immersed herself in community issues. It turned out that the cancer diagnosis was incorrect but she continued her involvement. She established a neighbourhood kindergarten which led to her being elected as a school trustee in 1948. In 1952 she became the first woman to chair the East York Board of Education. In 1958, she was elected to East York's town council. In 1960 she ran for the position of Reeve of the Township of East York against incumbent Jack Allen. The main issue at the time was uncontrolled development on land bordering the Don Valley beside Bayview Avenue. The development, later dubbed the Bayview Ghost, was a rallying cry for her campaign. She beat Allen by 5,065 votes to 3,458. Davidson was a dedicated politician, often attending community meetings, up to 40 per month. She was also a formidable debater, with an abrupt and abrasive style that annoyed her fellow council members. Yet the voters loved her and she was re-elected six times.