His public life began in 1409, when he was sent to the Council of Pisa, where he is said to have upheld the rights of the council. Back in England he took a prominent part in the prosecution of Wycliffites and Lollards, assisting at the trials of William Taylor (1410), Sir John Oldcastle (1413), William White (1428), preaching at St. Paul's Cross against Lollardism, and writing copiously on the questions in dispute ("De religione perfectorum", "De paupertate Christi", "De Corpore Christi", etc.). The House of Lancaster having chosen Carmelite friars for confessors, an office which included the duties of chaplain, almoner, and secretary and which frequently was rewarded with some small bishopric, Netter succeeded Stephen Patrington as confessor to Henry V of England, and provincial of the Carmelites (1414). No political importance seems to have been attached to such positions.