Bristol was, like most of the trading centres, Yorkist in sympathies, and in June 1451 Yonge distinguished himself by presenting to Parliament a petition from his constituents to the effect that the Duke of York should be recognised heir to the throne.
On 7 July 1455 Yonge was once more elected for Bristol, and in January 1456 claimed redress for his arrest and imprisonment, reminding the Commons in his petition that all members "ought to have their freedom to speak and say in the house of their assembly as to them is thought convenient or reasonable without any manner of challenge, charge, or punition therefore to be laid to them in any wise".
Yonge was naturally not elected to the Lancastrian Parliament which met at Coventry, a curious side-light on the division of parties being afforded by the fact that two "generosi de nativitate" took the place of the usual "mercatores" in the representation of Bristol.
He probably also sat in the Parliaments of 1461 and 1462–63, the returns for which are lost, and the triumph of his party under Edward IV secured Yonge much administrative employment and legal promotion.
He did lose his position during the puzzling rearrangement of the judiciary, when Edward IV regained his throne six months later, though he was exempted from the operation of the Act of Resumption in 1472–73.