Nellie Simpson was an activist and trade unionist, advocating for women's rights and peace. Simpson emigrated to Australia from Lancashire, England in 1928, living in Queensland before settling in Sydney. In the 1940s, she joined the Darlinghurst branch of the Australian Labor Party where she met campaigner Jessie Street, cementing her feminist and socialist ideologies. She spoke frequently about her political views on 2KY Radio Sydney from 1949-1965.

Simpson was a member of the Australian Labor Party, running multiple times for ALP executive boards, State and Federal parliament seats. Simpson's status as a member of the Federated Clerks' Union inhibited her success in these pursuits, as the union was accused as serving as front for the Communist Party of Australia. She was eventually elected to the New South Wales Australian Labor Party State Executive in 1969, but left the party shortly after, citing disillusionment by the shift from more socialist to centrist objectives.

She was awarded a certificate of appreciation from Queensland State Premier Peter Battie for her service to the ALP and the labour movement before her death.