Jacob Astley was born in Norfolk in 1579. He gained military experience fighting in the Netherlands during the Thirty Years War. In 1638 Charles I appointed him as Governor of Plymouth.
On the outbreak of the Civil War Astley joined the Royalists. At Edgehill (October, 1642) he was given command of the infantry. He also fought at Newbury (August, 1643) and Naseby (February, 1645). Later that year Astley replaced Charles Gerard as commander of the Royalist troops in South Wales.
Sir Jacob Astley died in 1651.