She was the first woman to be appointed Assistant Keeper in the Department of Coins and Medals and is regarded as a pioneer in what had previously been a male-dominated field.

Her 70th birthday was celebrated with the publication of a book of essays authored by 30 of her colleagues, collaborators and former students for whom Marion's name was "synonymous ... with the study of Anglo-Saxon coins at the British Museum".

[2][3] She joined the Department of Coins and Medals at the British Museum in 1963, and was appointed Assistant Keeper in 1965; she retired from her post in 1997.

She was a pioneer in the systematic recording of finds, as well as the application of an understanding of coin circulation histories on the dating of excavations; more generally, she worked to integrate numismatic and monetary system studies with archaeology and historical research, to the benefit of all these disciplines.

She held the post of president of the British Association of Numismatic Societies from 1986 to 1991; each year it sponsors a Marion Archibald Memorial Lecture at its annual conference.