Walmsley was born in Canberra. At the time of her election to the House of Assembly in 1979, she was 32, a qualified biochemist, a graduate student in politics at the Australian National University, and married with two children.
Walmsley was elected to the ACT House of Assembly in 1979, for the Division of Canberra. Peter Vallee was Labor leader from 1977 to 1982. He resigned, in order to allow a woman to lead Labor into the 1982 election. Walmsley then became the acting leader, but, as it turned out, a woman was not elected leader. The new leader was Ken Doyle, but he resigned after a year, in 1983, and Maurene Horder was elected leader in his place.
Walmsley resigned as a MHA in 1985, and was replaced by Rosemary Follett.
↑"LETTERS to the Editor". The Canberra Times. Vol.56, no.16, 999. Australian Capital Territory, Australia. 13 April 1982. p.2. Retrieved 25 May 2022– via National Library of Australia.
↑"ALP leader". The Canberra Times. Vol.56, no.17, 016. Australian Capital Territory, Australia. 30 April 1982. p.3. Retrieved 12 April 2021– via National Library of Australia.
↑"CORRECTION". The Canberra Times. Vol.58, no.17, 523. Australian Capital Territory, Australia. 20 September 1983. p.3. Retrieved 12 April 2021– via National Library of Australia.