Wilfley was born near Mexico, Missouri, and attended local country schools in his youth. An 1891 graduate of Clarksburg College, he graduated from Central Methodist College in Fayette, Missouri in 1894, teaching there for one year and at Sedalia High School in Sedalia, Missouri, for three. In 1899 he graduated from Washington University law school and began the practice of law in St. Louis.

From 1917 to 1918 he was the chairman of the city’s board of election commissioners; in 1918 he was appointed to the Senate as a Democrat to fill out the term of William J. Stone, who had died on April 14, 1918. Wilfley served from April 30 to November 5, and was the chairman of the Committee on Industrial Expositions. He unsuccessfully sought the Democratic nomination for the Senate seat, being defeated by Joseph Folk, who in turn lost to Republican Selden P. Spencer in November.

After leaving the Senate, Wilfley resumed the practice of law, becoming president of the Missouri Bar Association in 1925.