Daley's first elective office was in the Illinois House of Representatives, to which he was elected for the 9th district on November 3, 1936 alongside Democratic incumbents William J. Gormley and Peter P. Jezierny. Despite being a lifelong Democrat he was elected to the office as a Republican. This was a matter of political opportunism and the peculiar setup for legislative elections in Illinois at the time, which allowed Daley to take the place on the ballot of the recently deceased Republican candidate David Shanahan. Daley's name was not printed on the ballot due to the closeness of Shanahan's death to the election, but he was able to defeat Shanahan's friend Robert E. Rodgers.