He was the eldest son of William Forester of Dothill in Wellington, Shropshire (now Telford) and Catherine daughter and heir of William Brooke of Clerkenwell.
He was the only son of Brooke Forester of Dothill in Wellington and Elizabeth daughter and heir of George Weld of Willey Park.
William Forester succeeded to Dothill Park in about 1675 under the will of his helf-brother Richard Steventon (died 1659) and this became the main family seat at least until his grandson obtained Willey Park by marrying the heiress of George Weld.