Education
He was educated at Sydney Grammar School.
He studied at the University of Sydney. He graduated in 1883 with a Bachelor of Arts, winning the University Medal in Classics. He was appointed a vice-warden at the university's St. Paul's College in 1884, and from 1887 was a lecturer in English at the university.
Career
In 1895, Piddington was elected to the New South Wales Legislative Assembly for the electoral district of Tamworth, defeating the former Premier of New South Wales Sir George Dibbs. He was a delegate to the second constitutional convention in 1897-1898, where he campaigned against the proposed constitution, although supporting federation in general.He retired from politics in 1898. In 1910, Piddington was elected to the council of the University of Sydney. The following year, he was appointed as a Royal Commissioner by the Government of New South Wales to inquire into labour shortages, and was appointed a commissioner again in 1913 to inquire into industrial arbitration in New South Wales. During this time he continued to practice law and was employed at Sydney Boys High School.