He was born in to Cologne into a family from Aachen, hence his surname. Aachen began painting in Germany and then moved to Italy in 1574 to study further. He toured Rome and Florence, but evenutally settled in Venice. There he developed much of his mannersist technique.
He returned to Germany in 1588 and there won renown as a painter of portraits for noble houses. In 1592 he was appointed official painter of Holy Roman Emperor Rudolph II. Aachen thus moved to Prague where he stayed in Prague painting on commission from the emperor.