Born in Dublin to lawyer Lewis Goodbody and his wife Edith (née Pim), Williamson studied at Cheltenham Ladies College and in St Germain-en-Laye in Paris.
For part of World War I, she taught Braille at St Dunstan's in London, before becoming a director of J. J. Williamson & Sons, her family's tannery business in Canterbury.
[2] Soon afterwards, she defected to the Common Wealth Party, for which she stood in the 1943 Ashford by-election, taking 30.3% of the vote against a single opponent.
She stood in Canterbury at the 1945 United Kingdom general election but, facing both Labour and Conservative opponents, could only take 2.6% of the votes cast.
[3] Williamson rejoined Labour late in the 1940s, and stood in East Grinstead at the 1950 general election, and in Hastings in 1951.