William Hartnett graduated from the University of Virginia School of Law and practiced law in Illinois before serving as an attorney for the National Labor Relations Board. He was involved in the Democratic Party and labor union movement, running for various offices and serving in the Illinois House of Representatives. Hartnett spent nearly three decades in public service and legal practice, showcasing a blend of legal expertise and political engagement.

William Hartnett's political career showcases a blend of ideological agility and regional focus, as evidenced by his unexpected legislative alliances. His military background and legal experience suggest a strategic approach to policy that prioritizes stability and negotiation. Hartnett's engagement with both the Democratic Party and labor unions hints at a nuanced understanding of grassroots movements. His varied electoral attempts, from local to state supreme court levels, reveal a commitment to incremental political advancement.