A diplomat in the service of Philip the Good, duke of Burgundy. Bertrandon entered the Burgundian service in 1421 and was used mostly in diplomatic relations with France up to 1444.
In 1432 he was sent to the East with the mission of spying on those lands (primarily the Ottoman Empire) that had not been visited by Gilbert de Lannoy, who had previously undertaken a similar mission for Philip. From the Holy Land Bertrandon proceeded through Syria and Anatolia to Constantinople (mod. Istanbul, Turkey), and then (in the company of the Milanese ambassador) to the court of Sultan Murad II at Adrianople (mod. Erdine, Turkey), returning in 1439. From the chaplain of the Venetians at Damascus he obtained a Latin translation of the Qur’ān and of the deeds of Muhammad, which Duke Philip gave to Jean Germain, chancellor of the Order of the Golden Fleece.
Around 1455, after Philip the Good announced his intention to fight the Turks at the occasion known as the Vow of the Pheasant, Bertrandon gave advice to the duke regarding a crusade project devised by Giovanni Torzello in 1439. He also wrote up the intelligence gained on his travels as Le Voyage d’Outre-Mer.