He was knighted at the Parliament at Leicester by the infant Henry VI on 19 May 1426, and had control of his lands on 5 December 1427. He accompanied Henry VI to France in 1430, was summoned to Parliament from 25 February 1432 to 30 July 1460 by writs directed to "Leoni de Welles", and was a privy councillor before 12 November 1434. In 1436 he was with Humphrey, Duke of Gloucester, in the expedition sent to relieve the siege of Calais. He was a member of Henry VI's household before February 1438. From 12 February 1438 he resided in Ireland as Lord Lieutenant; according to Hicks, he 'failed to control the contending factions and resigned prematurely in 1442'. In 1441 he was particularly embarrassed at his inability to prosecute Thomas FitzGerald, the Prior of the Knights Hospitallers at Kilmainham, whom he accused of being party to the kidnapping of Lionel's brother William. The Prior produced a royal pardon, and no action was taken against him; nor would he release William until certain demands were met.