In 1575, Dormer succeeded to the considerable lands and estate of his father in Buckinghamshire and elsewhere, together with a fortune estimated by the Spanish ambassador to amount to 100,000 ducats.
[2] His half-sister, Jane, married the Spanish Ambassador, Gómez Suárez de Figueroa y Córdoba, 1st Duke of Feria.
Sir William Dormer was a friend of the influential Francis Russell, 2nd Earl of Bedford, whose patronage seems to have extended to William's son, Robert, and shielded the family somewhat from close scrutiny under the Penal laws despite the fact that Robert had married into the Catholic Montague family.
[citation needed] His daughter, Dorothy, married Sir Henry Huddleston, of Sawston Hall, noted for a number of priest holes.
[citation needed] Lord Dormer died on 18 November 1616,[2] aged 65, and was interred at All Saints' Church, Wing, where there is an impressive monument to his memory.