In Prague, he was represented in Litomyšl by the Official Nikolaus of Pelhřimov and by his brother Mathias, who served there as auxiliary bishop.
John of Neumarkt was appointed on 28 August 1364 by Pope Urban V. Bishop of Olomouc, as the existing incumbents Jan Očko of Vlašim had risen to the Archbishop of Prague.
A year later he received the title regalis capellae Bohemiae comes ("Count of the Bohemian royal chapel"), the honor and the right were connected, in the presence of other bishops – to crown the King of Bohemia and his on other occasions – with the exception of the archbishop of Prague put on the crown.
In 1367 John confirmed the statutes of the chapter of Kroměříž and in 1371 the establishment of the Augustinian monastery in Šternberk by his friend Albrecht of Sternberg.
Even after the death of the Wroclaw Bishop Preczlaw of Pogarell (1376) John of Neumarkt was the preferred candidate of the Emperor Charles IV and Pope Gregory XI.
Nevertheless, cathedral chapter chose the dean Dietrich of Klatovy, who was in 1378 confirmed in this office by the Avignon Pope Clement VII.
In a repeat ballot in 1380 John of Neumarkt was elected as the Bishop of Breslau, but died before the papal confirmation would have reached him.
1352 he was appointed prothonotary and, succeeding Jan Očko of Vlašim as chancellor of Emperor Charles IV.
For imperial coronation in Rome and traveled to Nuremberg Christmas, where he participated in the Reichstag and was at the court day at the announcement of the Golden Bull in attendance on 10 January 1356. he was late 1356 again in Metz, 1357 in Aachen and in Vienna, in 1359 in Wroclaw.
In the imperial chancery, he introduced a new instrument style, were used in the quotations from Latin classics and of the Church Fathers.
John maintained an orchestra, for secular celebrations designed, and strove for good education in schools.