He was born in London, the son of Sir William Wentworth, of
Wentworth Woodhouse, near Rotherham, a member of an old
Yorkshire family, and of Anne, daughter of Sir Robert Atkins of
Stowell, Gloucestershire. He was educated at St John's College,
Cambridge, became a law student at the Inner Temple in 1607, and
in 1611 was knighted and married Margaret, daughter of Francis
Clifford, 4th Earl of Cumberland. His relation, another Thomas
Wentworth, 1st Earl of Cleveland, fought during the Civil War.
In 1622 Wentworth's wife died, and in February 1625 he married
Arabella Holles, daughter of John Holles, 1st Earl of Clare. He
represented Pontefract in the parliament of 1624, but appears to
have taken no active part. He expressed a wish to avoid foreign
complications and "do first the business of the commonwealth."
In the first parliament of Charles I, June 1625, Wentworth again
represented Yorkshire, and showed his hostility to the proposed
war with Spain by supporting a motion for an adjournment before
the house proc