Leigh’s grandfather, Sir Thomas, a wealthy London merchant who served as lord mayor in 1558-9, acquired extensive lands in Warwickshire in the mid-sixteenth century. His second son, who established a seat at Stoneleigh, was the ancestor of Sir Thomas Leigh, 2nd bt*. His youngest son, Leigh’s father, settled at King’s Newnham, and by 1608 this branch of the family owned more than 21,000 acres in the east of the county.
Made a knight of the Bath at the start of James I’s reign, Leigh again represented Oxford in the 1604 Parliament. He appears not to have participated in debates, and in the first couple of sessions he received only two committee nominations, concerned with church attendance (27 June 1604) and repairs to a road near his Surrey estates (2 Apr. 1606).
Although Leigh’s best prospect for advancement at Court ended with Prince Henry’s premature death in 1612, the continuing prominence of his father-in-law, now lord chancellor Ellesmere, ensured that he still benefited from government patronage. In the 1614 parliamentary elections, Leigh obtained a seat at Leicester through the chancellor of the duchy of Lancaster, Sir Thomas Parry*.
In 1618 Leigh arranged the marriage of his eldest son (Sir Francis Leigh, 1st bt.*) to a niece of the royal favourite, the marquess of Buckingham, but this new connection scarcely compensated for the death of his principal patron, Lord Ellesmere, in the previous year. The lord chancellor’s demise apparently prompted him to settle in Warwickshire again, where he was added to the local bench, and in 1618-19 served as sheriff. Even though his father was still living, Leigh seems to have held the legal title to much of his patrimony as early as 1608, probably under the terms of his first marriage settlement, the details of which are lost. It was therefore as one of the county’s principal landowners that in November 1621 he was chosen knight of the shire at the by-election caused by Sir Fulke Greville’s elevation to the peerage. It is unlikely that his somewhat distant ties to Buckingham influenced the election’s outcome, as the favourite did little to advance Leigh’s son around this time. Leigh presumably took his seat in the Commons before the session ended three weeks later, but left no trace in its records.
Leigh drew up his will on 7 Feb. 1625, confident that he would be ‘made partaker of [Christ’s] most glorious presence and everlasting kingdom’. He requested burial at King’s Newnham with his mother, and left his father £10 for a mourning ring. The disposition of his property was already settled, but he bequeathed £500 each to his younger son and his remaining unmarried daughter. His charitable legacies included £4 for the Warwickshire parish of Church Lawford to buy a new communion chalice, the design of which was to be decided by the incumbent, John Slatter, Leigh’s ‘teacher and confessor’. He died in the following August, predeceasing his father, though it was his son Sir Francis who proved his will on 6 Jan. 1626.