Manvydas was first recorded in written sources in May 1423 when he affixed his seal to the Treaty of Melno. In August 1431, he witnessed the truce of Chortoryisk that Grand Duke Švitrigaila concluded with the Teutonic Order (see Polish–Teutonic War (1431–1435)). At the time, he was a starosta of Kremenets. Manvydas and his family continued to support Švitrigaila after he was deposed in August 1432. His uncle Jurgis Gedgaudas was captured in the Battle of Ashmyany and reconciled with the new Grand Duke Sigismund Kęstutaitis. Manvydas continued to support Švitrigaila in the Lithuanian Civil War (1432–1438). In 1436–1437, he claimed the title of Voivode of Podolia.