Admitted to the bar in March 1867, Wilkin joined Scholfield's practice as a partner. Wilkin was a
Republican and was a presidential elector during the
1872 United States presidential election. However, the following year Scholfield was elected to the
Supreme Court of Illinois, ending the partnership. Wilkin continued to practice in Marshall until 1879. That year, he was elected to the 4th
Illinois Circuit Court. He served until 1885, when he was elevated to the 4th District,
Illinois Appellate Court. Wilkin moved to
Danville, Illinois that year. In 1888, he was elected to the Supreme Court of Illinois to fill the vacancy of
John M. Scott, who had declined re-election. Wilkin was re-elected in 1897 and 1906, serving a total of nineteen years. He was chief justice in 1894 and 1901. ==Personal life==