William L. Dill was born in 1874 in Freeburg, Pennsylvania, and later moved to Paterson, New Jersey, at age 12. He began his career in public service as a secretary to the Mayor of Paterson and later served as the President of the Paterson Finance Board. Dill transitioned to state-level roles, including Secretary to the New Jersey Senate and Assistant Secretary of State, before becoming the State Motor Vehicle Commissioner. After stepping down from the latter position, he sought the Democratic nomination for Governor of New Jersey in 1928, though he was unsuccessful. He was appointed to the New Jersey Court of Errors and Appeals in 1933, serving until the court's abolition in 1948.

William L. Dill's political career reveals a calculated approach to navigating regional power dynamics, particularly through his ties to Democratic party boss Frank Hague. Despite losing two gubernatorial races, Dill's repeated appointments to the New Jersey Court of Errors and Appeals suggest a strategic alignment with entrenched political structures. His ideological positioning, often criticized for its association with "bossism," hints at a nuanced understanding of local power mechanisms. Dill's rhetorical style likely emphasized loyalty and regional stability, though the specifics remain open to interpretation.