William was born in 1814 to Robert and Jane (nee Derry) Pearse at Launceston. William became a surgeon operating out of his Castle Street Surgery. In 1839 he married Mary Spry at Launceston and together they had three children, William Henry, Ernest and Mary Elizabeth. His wife died in 1855 aged just 36. In 1856 William married Mary Ann Lobb at Launceston.
In 1875 he was appointed the Medical Officer for the Local Health Board. William was also a member of the Launceston Borough Council being Mayor in 1872. He was a non-conformist, being part of the Congregational Church in Launceston.
He was also a keen cricketer and was chairman of the Launceston and Werrington Cricket club for a period in the early 1860’s.
William died on Christmas eve 1892 and was interred at the Bowling Green Cemetery in Horse Lane (Dockacre Road).