Longbridge returned to her native Westmoreland in the 1930s, but was unable to find employment during the
Great Depression. Bustamante and Longbridge formed a long personal and professional relationship that would last for decades. She served as his secretary through his years as a
trade unionist and as a politician, until he became
Prime Minister of Jamaica in 1962. That year they married. As the Bustamante Industrial Trade Union was the largest organization in Jamaica at the time, Longbridge was arguably the most influential woman in Jamaica. Bustamante later described the role of women in the Jamaican trade union movement in her memoir, "We women were the mainstay of the union's organisation, though we could hardly have functioned without the brave men who toiled day and night, facing all sorts of criticism and opposition as they tried to help the workers." She also played a prominent role in the founding of the
Jamaica Labour Party by Alexander Bustamante in July 1943. In 1951, Longbridge agreed to run for political office in Eastern Westmoreland. She lost the election, which pleased her as she had reluctantly agreed to seek elected office. At the time, the
Jamaica Gleaner newspaper described her as "the happiest loser" of the election. Jamaican political and union life during the late colonial and post-independence eras centered largely on the rivalry between Bustamante and
Norman Manley. While the two men, who were cousins and rivals for political power, often feuded in public, relations between Gladys Bustamante and Manley's wife,
Edna Manley, were much more cordial. ==Marriage==