He was born in Modum as a son of physician Hans Gabriel Sundt Dedichen (1836–99) and his wife Caroline Henriette Fredrikke Thaulow (1836–1917).
He was a brother of psychiatrist Henrik Dedichen and a maternal grandson of Heinrich Arnold Thaulow.
He attended Trondheim Technical School (now Norwegian University of Science and Technology).
In 1904 he was awarded the Crown Prince's gold medal (Kronprinsens gullmedalj) for the paper Bestemmelse av basiske ringsystemers affinitetsstørrelse.
[2] Through his son, shipbroker Jan Kurt Dedichen, he was a father-in-law of Aase Bye.