Career
He published many historical and genealogical works, the most important being En gammel Christiania-slægreat Optegnelser om familien Collett og Christianias fortid (1883) and Gamle Christiania-Billeder (1893). Alf Collett was the second son of Peter Jonas and Camilla Collett.
He had one older brother Robert, a notable zoologist, and two younger brothers.