He was the son of David B. Stewart (1832–1915), the first Mayor of Ithaca.
He attended the public schools in Ithaca, and then became a partner in his father's wholesale grocery business.
Stewart was a member of the New York State Assembly (Tompkins Co.) in 1894 and 1895.
His widow died about half a year later, and the estate became a party in a case argued before the U.S. Supreme Court concerning the payment of estate taxes.
Stewart Park in Ithaca was named in his honor.