His father commanded a troop of horse against the Duke of Monmouth at the Battle of Sedgemoor in 1685 and died in 1691.
[1] He succeeded to the family estates in Dorset, Hampshire, Surrey and Somerset on the death of his elder brother Thomas in 1711.
[2] Chafin was returned unopposed as Tory Member of Parliament for Dorset at the 1713 general election.
By 1748 he was in financial difficulties, and had to obtain an Act of Parliament to allow him to sell some of his settled estates to pay his debts.
At a meeting at Dorchester in August 1753, he declined nomination for the next election, being according to an electoral survey "ruined in his affairs", and did not stand in 1754.