He was born in Nes i Hallingdal as a son of district stipendiary magistrate Frants Henrik Meidell and Olivia Annette Caroline Arntzen.

[3][4] Garup Meidell finished his secondary education in 1885 and graduated from the Royal Frederick University with the cand.jur.

[3] He notably took part in the liquidation of Den norske Discontobank in 1901 and Industribanken in 1902.

[1] He was also appointed by the state to the control committee of Andresens og Bergens Kreditbank, when this bank was placed under public administration in 1923.

[3] He chaired the supervisory council of Elektrisk Bureau,[5] and was a board member of the Norwegian Bar Association.