Champernowne belonged to one of Devon’s oldest gentry families, which had settled in the county during the twelfth century, and produced a knight of the shire in 1298. His grandfather, Sir Arthur†, a younger son, acquired Dartington Hall in 1559, and sat for the nearby borough of Totnes in the second Elizabethan Parliament. Sir Arthur was a staunch Protestant who helped to suppress the 1549 Prayer Book rising and participated in Wyatt’s rebellion. During the French wars of religion he espoused the Huguenot cause, and married his heir Gawen to the daughter of one of its leaders. This union proved stormy, however, nearly ending in divorce in 1582. Gawen continued his father’s struggle against international Catholicism, fighting alongside his father-in-law in France, and providing one of the ships that sailed against the Spanish Armada, though his prominent role in Devon’s defence prevented him from joining the fleet.
Champernowne was aged only 11 when his father Gawen died in 1592. His wardship was acquired by his mother, who subsequently married a Somerset gentleman, Thomas Horner†. By his own estimate, Champernowne inherited personal goods, leases and ships worth around £4,000, with an annual income of perhaps £400. However, this estate was comparatively small by Devon gentry standards, a fact which probably explains his rather late appointment as a local magistrate.
Champernowne’s long-running dispute with the lessees of Totnes’ town mills seems not to have damaged his relations with the corporation, and indeed he sat for the borough in the 1624 Parliament. However, he left no trace on the Commons’ proceedings. He presumably backed the election of his cousin Sir Edward Seymour* at Totnes in the following year.
Shortly after his return to Devon, Champernowne and other local billeting commissioners were entertained by the corporation ‘at two sundry times about removing soldiers’ housed in the town in the aftermath of the failed Cadiz expedition of 1625. These meetings bore fruit in August 1626, when the commissioners persuaded the Privy Council to relocate the troops.
The renewed war with Catholic Europe apparently stirred Champernowne to emulate the military exploits of his father and grandfather. He was recorded as the owner or part owner of eight merchant ships licensed as privateers between 1626 and 1630, though their operations may not have been financially lucrative. In 1634 he secured from the king the reversionary title to Plympton priory, Devon after claiming that ‘during the late war with Spain he ... suffered much’.