Arnoldus Koren was born in Bergen, Norway. He father Niels Johansen Koren (1718-1784) was a sea captain and later merchant in Bergen. His elder brother was Ulrich Wilhelm Koren (1747-1826) who served as district governor in Stavanger. He completed Bergen Cathedral School in 1784. He started the divinity school in University of Copenhagen prior to earning his law degree in 1789. Trained as a lawyer, he served as district judge and magistrate (Sorenskriver) in Hardanger and Voss from 1799.
