Background
He was the son of James Denniston (ca 1770–1825) and Prudence Morrison Denniston.
He was the son of James Denniston (ca 1770–1825) and Prudence Morrison Denniston.
He served as an officer of the New York State Militia and as a Justice of the Peace in Blooming Grove. He was appointed by Governor William L. Marcy a judge of the Court of Common Pleas of Orange County
In the Senate, he was Chairman of the Committee on Canals. As a Republican, he ran for New York State Comptroller in 1857 but was defeated by Democrat Sanford East. Church.
He ran again in 1859 and was elected, being in office from 1860 to 1861.
Republican Party, Democratic Party.
He was a Democratic member of the New York State Assembly (Orange Company) in 1835, 1839 and 1840. He was a member of the New York State Senate (2nd Doctorate) from 1841 to 1847, sitting in the 64th, 65th, 66th, 67th, 68th, 69th and 70th New York State Legislatures.