She then became a tractor-trailer driver for Pan American Airlines at JFK Airport— the airline's first female trucker. She was a member of Local 504, Air Transport Division, TWU. For 11 years she represented the members in her local, first as an unofficial activist and later as a top leader. She experienced the difficulties of trying to represent the needs of the women, a distinct minority within the total membership. In 1991 Pan Am went into bankruptcy and then out of business, taking thousands of jobs with it.

Sullivan enrolled in Career Connections, a program for displaced workers, and studied at Adelphi University to become a paralegal. She received a scholarship established by tradeswomen's activist Cynthia Long that allowed her to attend Cornell Labor Studies Program for Trade Union Women.

In the next phase of her career she was director of the Women's Project, a new initiative of the Association for Union Democracy (AUD), where she was a public advocate for women workers. Sullivan worked with tradeswomen and their organizations in New York City and nationwide.

When Teamster Local 295, the JFK Airport local, was placed under trusteeship after years of mob control, the administrator of the trusteeship offered Sullivan a job as the local's business agent. In turn that experience led to her appointment as trustee of Teamster Local 851, also at JFK Airport.

Finally, she became a top union official in one of New York City's most powerful blue-collar institutions—the 40,000-member Local 100, TWU—the bus and subway workers' union. As director of its Grievance and Discipline unit, she supervised the union representatives, attorneys, and arbitrators hired jointly by the union and management to represent members in cases of disciplinary charges and grievances.

Sullivan's oral history details her involvement in the struggle for female representation within trade unions, her growing self-confidence in her ability to lead, and the challenges of cleaning up mob-ridden unions.