Yonge was baptized on 8 September 1653, the son and heir of Sir Walter Yonge, 2nd Baronet (c.1625–1670) of Great House in the parish of Colyton, Devon and his wife Isabella Davie, daughter of Sir John Davie, 1st Baronet, of Sandford, Devon.
[3] His father had purchased the manor of Mohuns Ottery in the parish of Luppit, Devon,[4] and had started to build a new residence there, which the 3rd Baronet discontinued, preferring the situation of Escot.
He was returned unopposed for Honiton again at the 1695 English general election and signed the Association promptly.
At the 1698 English general election he was returned unopposed again for Honiton and continued to act as teller and speak for the Administration.
In November 1701, he resigned as commissioner of customs so that he could retain his parliamentary seat in accordance with the new place clause and was returned in a contest in the second general election of 1701.
He was returned in a contest at the 1705 English general election, and voted for the Court candidate for Speaker on 25 October 1705.