Assumed national roles in WILPF, cementing her status as a key figure in U.S. peace advocacy.
Beginning in January 1934, Mildred Olmsted started taking on national-level responsibilities within the Women's International League for Peace and Freedom (WILPF). This transition marked a significant escalation in her influence as she became a major figure in shaping the organization's direction in the United States. Her work in this capacity included developing strategic priorities, liaising with international peace bodies, and amplifying the League's campaigns across the nation. Through her leadership, Olmsted played a foundational role in the efforts to promote disarmament and peace amidst rising global tensions in the prelude to World War II.