After his election, Daley quickly moved back to the Democratic side of the aisle. After the death of incumbent Democratic Senator Patrick J. Carroll in 1938, Daley was elected to the Illinois Senate. That year Gormley and Jezierny were successfully reelected with Republican William S. Finucane taking the third spot. In 1939, Illinois State Senator William "Botchy" Connors remarked of Daley, "You couldn't give that guy a nickel, that's how honest he is." Daley served as Minority Leader of the Illinois Senate from 1941 through 1946. He suffered his only political defeat in 1946, when he lost a bid to become Cook County sheriff.