Born in County Westmeath, Alton attended The High School, Dublin. He graduated from Trinity College Dublin in 1896 with honours in classics and philosophy, having been elected a Scholar of the College in 1894. He was elected to the House of Commons of Southern Ireland at the 1921 elections, representing the University of Dublin constituency as an independent Unionist, he did not participate in the Second Dáil. He was re-elected for the same constituency at the 1922 general election and became a member of the Third Dáil. He was re-elected at the next five general elections until the University of Dublin Dáil Éireann constituency was abolished in 1937. He served as a member of the 2nd Seanad and the 3rd Seanad representing the Seanad Éireann Dublin University constituency until 1943 when he retired from politics.
His sisters were teachers of music at Wesley College Dublin. One taught violin, the other taught piano. His nephew Bryan Alton was a member of Seanad Éireann from 1965–73.
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