ambler was the second son of humphry ambler (~1681–1745) barrister of stubbings park maidenhead and bream's buildings chancery lane, and his wife ann, daughter of charles bream (~1662–1713) timber merchant of bridewell and bream's buildings. charles's crippled (by a fall when aged eight) epileptic elder brother, humphry, died of a consumption unmarried in 1752. the ambler mansion house at stubbings was built by humphry ambler on the site of a small portion of forest acquired with his stepfather richard bassett of white waltham and harvested for shipbuilders.