William Milliken was born into a family with a strong legacy in public service. He graduated magna cum laude from high school and attended Yale University. During World War II, he served in the Army Air Corps, flying 50 combat missions and earning multiple military honors. Milliken later managed a family business before transitioning to a political career. He held various state-level positions, culminating in a record-setting tenure as Michigan's governor. Post-politically, he contributed to corporate boards and environmental advocacy.

William Milliken's political identity is marked by a blend of regional advocacy and bipartisan pragmatism. His long tenure as Michigan's governor saw him form the Council of Great Lakes Governors, revealing a localized focus on environmental stewardship. Milliken's endorsement of Democratic candidates, including John Kerry and Hillary Clinton, underscores an ideological flexibility that diverges from traditional party lines. His support for same-sex marriage further highlights an unexpected progressive stance within a traditionally conservative framework.