An outspoken advocate of prohibition, he made substantial donations to the Prohibition Party and Indiana's prohibitionist leader Frank Hanly. Haynes ran an unsuccessful campaign in Indiana for the U.S. Senate in 1916 as a prohibition candidate and remained active in the party until prohibition became law. Later, he became a philanthropist and served two terms as president of the YMCA, five years on the Indiana Board of Education, and was an active member of the Presbyterian church. After his death from complications arising from influenza, his Kokomo mansion was converted into the Elwood Haynes Museum and is open to the public where many of his original inventions and automobiles are on display.