Walpole was returned to Parliament as one of two representatives for Norfolk North in 1868, a seat he held until his death eight years later.
Family
Walpole married his second cousin Laura Sophia Frances, daughter of Francis Walpole and Elizabeth Knight, in 1852. They had several children, including Robert Walpole, who succeeded as fifth Earl of Orford in 1894. Walpole died in April 1876, aged 53. His wife survived him by 25 years and died in January 1901.