Knollys was the son of Sir
Francis Knollys, Treasurer of the Royal Household, and
Catherine Carey, Lady of the Bedchamber to Queen Elizabeth I. He quickly entered the Queen's service. He grew up in
Rotherfield Greys in
Oxfordshire and
Reading in
Berkshire. In 1572, he was elected
Member of Parliament for
Reading. He was Keeper of
Syon House and steward of Isleworth in 1577 and usher of Tower mint from 1577 to 1582. From about 1583, he was a
J.P. for Breconshire. He was elected MP for Reading again in 1584 and 1586. In 1587 he became a
gentleman of the privy chamber. In 1589 Knollys was elected MP for Reading and
Breconshire and chose to sit for Breconshire. He became
Deputy Lieutenant in 1590 and
Custos Rotulorum in about 1592. In 1593 he was re-elected MP for Breconshire. He was elected MP for Breconshire again in 1597 and 1601. By 1603, he was
esquire of the body and in July 1603 was made a
Knight of the Bath. He was re-elected MP for Breconshire in 1604. He enjoyed sports and played bowls with the Earl of Shrewsbury. He also took part in tilting competitions and was seriously injured in November 1602. He was brother of
Edward,
Francis,
Richard,
William and
Henry Knollys who were all MPs. ==Ancestry==