Upon graduation, he returned to Chicago, and covered the police beat for the "Chicago Tribune". Patterson served in the Illinois House of Representatives as a Republican in 1903 and 1904, married and was the father of three daughters by 1906. The youngest, Alicia, explained, "He had wanted a boy, instead of three daughters in succession, and that meant one of the Patterson girls would have to be his substitute son." Nearly 20 years later, in 1923, after his three daughters had become young women, his mistress (and future wife) gave birth to his only son, James Joseph Patterson, in England.