He was appointed to Saint-Gilles, in Provence, to continue his education in France, as was typical for Milanese youths of his day. He was recalled in 1111 by Olrico da Corte, the vicedominus, and ordained a presbyter on 1 September by Ariald, Bishop of Genoa. The embattled Grossolano took that moment to go to the Holy Land, leaving Guazzone Comino and Amizone da Sala in charge with Arderic, Bishop of Lodi, as his acting vicar. Almost immediately a council of equal numbers of supporters and opponents of the archbishop convened in his absence and, deposing him, elected Jordan to his place on New Year's Day. In February, Landulf, Bishop of Asti, consecrated the new archbishop to his post and, together with Ariald and Mainard of Turin, did homage to Jordan as his suffragans. Only Atto, Bishop of Acqui, and Arderic of Lodi refused to do homage to the new bishop and remained loyal to Grossolano. On 6 December, Mainard formally deposed Grossolano at the altar in S. Ambrogio. Jordan and Bernard, Bishop of Pavia, proclaimed a general peace throughout Lombardy, of which Jordan was now the primate. He then received the recognition of Pope Paschal II, legitimising the irregularities of his election.
In August 1113, Grossolano returned from his pilgrimage. Tensions were raised in the city of Milan, where the old archbishop still had some supporters. Finally, on 11 March 1116, Paschal declared Grossolano's transferral from the see of Savona to that of Milan to be invalid and thus null. He was transferred back to Savona and Jordan was again confirmed as the legitimate Ambrosian pontiff.
Jordan was a staunch papist (later Guelph) and Milan under him was a centre of anti-imperial feeling. His episcopate saw the citizens of Milan grow in power. In 1116, they began electing consuls, with all the saecular powers theretofore reserved for the bishops. In a solemn ceremony at S. Tecla, Jordan even excommunicated the reigning emperor, Henry V.
Jordan interfered extensively in his suffragan diocese. He deposed Armanno da Gavardo from Brescia and made the elected Villanus bishop there. He deposed Ugo da Noceto in Cremona and raised Oberto da Dovara in his place. He intervened in the episcopal succession to Como in 1118 and sparked a nine-year war (until 1127) between the cities of Milan and Como. In Spring 1120, he met the returning Pope Callistus II at Tortona (the pope had been visiting France). He died in the fall of that year and was buried in his basilica. He was succeeded by Olrico, who had first recalled him from Provence.