He was named registrar in the Surrogate Court of the Midland District in 1814. Hagerman was one of the members of the establishment who argued with Robert Gourlay when Gourlay held meetings in Kingston. In 1820, he was elected to represent Lennox & Addington in the Legislative Assembly of Upper Canada.
In 1814, Hagerman held a position as registrar at the Surrogate Court of the Midland District. He belonged to the establishment that opposed Robert Gourlay when Gourlay convened meetings in Kingston. In 1820, he was chosen to represent Lennox & Addington in the Legislative Assembly of Upper Canada.