Arnot's career at the State Library of New South Wales began with the role of temporary junior library assistant in March 1921.
She was acutely aware of the disparity of the wages earned by women, for example a male cleaner was paid considerably more than a female graduate library assistant when she joined the library staff.
She became an active campaigner for equal pay for women from 1937 onwards.

Arnot progressed through a number of roles at the library, including cataloguing serials, extension librarian providing services to country areas of New South Wales, head cataloguer and acting Mitchell librarian from 1956–1958.
She also received funding from the British Council and the Carnegie Corporation of New York which allowed her to travel in 1948–1949 to study library services in Great Britain and North America.
Despite acknowledgement by the Library trustees of her achievements as Acting Mitchell Librarian during the absence of Phyllis Mander-Jones, Arnot was unsuccessful in applying for the position of Mitchell Librarian in 1958.

In 1961, Arnot was a member of the Australian delegation to the First International Conference on Cataloguing Principles, which was held in Paris.
Amongst the delegates representing fifty-three countries, including Dr S. R. Ranganathan from India and Seymour Lubetzky from the Library of Congress, Jean Arnot's contributions to the discussions are recorded in the conference papers.

Arnot retired as head cataloguer in 1968 after a distinguished career of over 47 years of service.
In her retirement she held the voluntary role of honorary librarian of the Royal Australian Historical Society from 1969 to 1980.
Arnot's career at the State Library of New South Wales began with the role of temporary junior library assistant in March 1921. She was acutely aware of the disparity of the wages earned by women, for example a male cleaner was paid considerably more than a female graduate library assistant when she joined the library staff. She became an active campaigner for equal pay for women from 1937 onwards.
Arnot progressed through a number of roles at the library, including cataloguing serials, extension librarian providing services to country areas of New South Wales, head cataloguer and acting Mitchell librarian from 1956–1958. She also received funding from the British Council and the Carnegie Corporation of New York which allowed her to travel in 1948–1949 to study library services in Great Britain and North America. Despite acknowledgement by the Library trustees of her achievements as Acting Mitchell Librarian during the absence of Phyllis Mander-Jones, Arnot was unsuccessful in applying for the position of Mitchell Librarian in 1958.
In 1961, Arnot was a member of the Australian delegation to the First International Conference on Cataloguing Principles, which was held in Paris. Amongst the delegates representing fifty-three countries, including Dr S. R. Ranganathan from India and Seymour Lubetzky from the Library of Congress, Jean Arnot's contributions to the discussions are recorded in the conference papers.
Arnot retired as head cataloguer in 1968 after a distinguished career of over 47 years of service. In her retirement she held the voluntary role of honorary librarian of the Royal Australian Historical Society from 1969 to 1980.
Jean Arnot