He was elected to two terms in the Ohio Senate, and owned a large amount of stock in the Allen County Democrat newspaper.

Mehaffey's mother died in March 1899, and his father in November 1907 married Mary E. Mount of Chatham-Kent, Ontario, Canada.

As both his grandfather and father were very active in Democratic politics, he won entry to the United States Military Academy at West Point.

[1] Mehaffey served in Rock Island, Illinois; Memphis, Tennessee; and New Orleans, Louisiana, until November 21, 1911, at which time he was transferred to the Panama Canal Zone.

He remained in the office only until September 1, when he was assigned to the Chief of Engineers of Washington, D.C.[1] On July 1, 1915, Mehaffey was made a member of the Board of Road Commissioners for the recently created Territory of Alaska.

[6] During his tenure there, Mehaffey was promoted to captain on July 1, 1916, and to brevet major on August 5, 1917, almost four months after the American entry into World War I.

He only served there briefly, however, and on October 27 was assigned an assistant to the Engineer Purchasing Office in London, England.

In July 1920, Mehaffey was promoted to major and assigned to the American Liquidation Mission in England, where he helped to dispose of excess military materiel.

[9] On July 16, 1925, Mehaffey was appointed assistant to the executive officer of the Arlington Memorial Bridge Commission, an independent agency of the U.S. federal government established by Congress.

He also supervised the 1927 conversion of the attic of the White House into a third floor with bedrooms, bathrooms, and office space.

[6] Mehaffey was assigned to the Panama Canal Zone in December 1929, where he served as assistant maintenance engineer.

Upon his promotion, he was assigned to be executive assistant to the Chief Engineer of the Works Progress Administration (WPA).

[12] Mehaffey entered the United States Army War College in September 1938 and graduated in June 1939.

[8] He was then named post commander of Fort DuPont in Delaware on July 1, 1939, where he once again served with the 1st Engineer Regiment.

[17] After attacks by Nazi German submarines in June 1942, an anti-submarine air patrol was established at Coco Solo naval base near the eastern entrance to the canal, and the United States Navy began convoying cargo ships to and from the area.

[21] Although canal traffic plunged in 1942 to levels not seen since 1918, the invasion of France and collapse of Nazi Germany shifted hundreds of thousands of troops to the Pacific theater.

He suffered a brief, undisclosed illness in January 1953, and died at Walter Reed General Hospital on February 18, 1963.