 Both his parents died before he was 11 and he was brought up by his maternal grandmother, Lady Mason, who had assumed administration of his father's affairs.When he came of age at 21, he found great fault with the management of his property, and the resulting coolness between himself and his grandmother was exacerbated by his possession of the Mason manor of Sutton in Surrey, which he had inherited from his mother, but which Lady Mason believed belonged rightly to the children of her other daughter, Anna Mason, the notorious Countess of Macclesfield, the divorced former wife of Charles Gerard, 2nd Earl of Macclesfield.In 1713 Brownlow was elected as a Member of Parliament for Grantham.