Background and education Bayly was the eldest son of Sir Edward Bayly, 1st Baronet, and Dorothy, daughter of the Hon. Oliver Lambart. He was educated at Trinity College, Dublin. He succeeded his father as second Baronet in 1741.

Family Bayly married firstly Caroline Paget, daughter of Brigadier General Thomas Paget, Governor of Minorca (died 1741) and Mary Whitcombe, in 1737. They had several children, including Paget Bayly, a Captain in the Royal Navy, and Nicholas Bayly, also Member of Parliament for Anglesey. After his first wife's death on 7 February 1766, he married secondly Anne (née Hunter). There were no children from this marriage. Bayly died in December 1782 and was succeeded in the baronetcy by his eldest son from his first marriage, Henry, who had already succeeded as 10th Baron Paget through his mother in 1769 and was later created Earl of Uxbridge. He was the father of Henry Paget, 1st Marquess of Anglesey, hero of the Battle of Waterloo. Lady Bayly died in May 1818.

Family Bayly married firstly Caroline Paget, daughter of Brigadier General Thomas Paget, Governor of Minorca (died 1741) and Mary Whitcombe, in 1737. They had several children, including Paget Bayly, a Captain in the Royal Navy, and Nicholas Bayly, also Member of Parliament for Anglesey. After his first wife's death on 7 February 1766, he married secondly Anne (née Hunter). There were no children from this marriage. Bayly died in December 1782 and was succeeded in the baronetcy by his eldest son from his first marriage, Henry, who had already succeeded as 10th Baron Paget through his mother in 1769 and was later created Earl of Uxbridge. He was the father of Henry Paget, 1st Marquess of Anglesey, hero of the Battle of Waterloo. Lady Bayly died in May 1818.

Political career Bayly was returned to parliament for Anglesey in 1734, a seat he held until 1741, and again between 1747 and 1761 and 1770 and 1774. In 1761 he was appointed Lord Lieutenant of Anglesey, which he remained until shortly before his death in 1782.

English Lieutenant James Cook's expedition in HM Bark Endeavour charts the eastern coast, and claims it for the British Crown. Australia dubbed 'terra nullius' i.e., according to the European legal precepts of the era, it was 'owned' by no-one.