 He was a member of the school board of West Lafayette, Ohio, for eight years.He was a member of the Ohio House of Representatives from 1935 to 1940, serving as minority whip from 1937 to 1939 and as majority leader and speaker pro tempore in 1939 and 1940.McGregor was elected as a Republican to the Seventy-sixth Congress to fill the vacancy caused by the death of William A. Ashbrook.