Russell was descended from Stephen Russell alias Gascoigne, a vintner of Weymouth, Dorset, who sat for the borough in 1395. During the following century the family built up its property in the county, mostly by marriage, and then achieved national prominence under the Tudors.
Russell spent part of his youth in Ireland, but after his marriage settled at Northaw. In 1610 he was returned for Lyme Regis, in the by-election caused by the absence overseas of Sir George Somers*. Although Russell took a keen interest in his Dorset roots, later commissioning a report on ancestral memorials at Dorchester and Swyre, the family by this time had only tenuous ties with the county, and it is unclear by what means he was nominated for this seat.
In 1613 Russell succeeded to his father’s peerage, and he soon became the effective head of the family, four years later purchasing most of the estates of his bankrupt cousin, the 3rd earl of Bedford. With the help of Sir Robert Cotton* he secured the re-enfranchisement of Amersham, Buckinghamshire in 1624, and in the same year began to provide a safe seat at Tavistock, Devon, for John Pym*.
