The 3rd Earl of Devonshire inherited the title age 11 on his father's death. He was educated by his mother and his father's former tutor, the philosopher and author Thomas Hobbes.
Both the 3rd Earl and his mother, Christian Bruce, were staunch Royalists when the Civil War began in 1641, and the family dedicated large amounts of money to raising regiments for Charles I.
Colonel Charles Cavendish, the 3rd Earl's younger brother, was celebrated for his bravery but was killed on the battlefield in 1643.
The 3rd Earl himself, mindful of his duty to protect his family name, departed for the safety of the continent and did not return until after the war was over.
Chatsworth was occupied by both sides during the Civil War, and the 3rd Earl did not return to the house until peace was restored with the Restoration of the monarchy. Although he reconstructed the principal rooms in an attempt to make them more comfortable, the old Elizabethan house was becoming increasingly outdated and unsafe.
The 3rd Earl of Devonshire married Lady Elizabeth Cecil, daughter of William Cecil, 2nd Earl of Salisbury, on 4th March 1639. Together they had two children.
He died in 1684 and was succeeded by his eldest son, William.