Johann Arnold de Reux was the youngest child of the Cologne merchant Johann de Reux and his wife Katharina Dulman. In 1681 he enrolled at the University of Cologne. He graduated with a Dr.jur.utr. away. In 1683 he received minor ordinations and a year later received a canonship at the Cassius Monastery in Bonn. In 1690 he received the subdiaconate and in 1691 the diaconate. In 1699 he donated the All Souls’ Altar in Bonn Minster.
After his predecessor Johann Werner von Heyder had been appointed auxiliary bishop in 1703, he took over his position as vicar general in 1704. In the years 1716 and 1717 he conducted extensive visitations in the Duchy of Westphalia. This was followed by visitations in the Eifel (1718-1721). In 1720 he was appointed canon. The new Archbishop Clemens August initially left him in office after 1723. Since there was hardly any contact between the two, de Reux asked in 1730 to be released from the Vicariate General and was then appointed an official. He held this position until 1739.
His connection to Steinfeld was not only due to the seminary near the Gereonskirche, which was run by the Premonstratensians from Steinfeld.
