He was born in Kolbu as a son of attorney Bernhard Dunker Stabell (1878–1929) and Dorothea Antoinette Platou (1883–1964).
After studying at the London School of Economics in 1937, he was hired as a secretary in the employers' association Jordbrukets og Meierienes Arbeidsgiverforening.
In 1940, following the occupation of Norway by Nazi Germany he was hired as a secretary in the Norwegian Ministry of Justice-in-exile in London.
He was promoted to assistant secretary, but returned home after the Second World War to work as an attorney in Oslo from 1945 to 1949.
[3] Stabell chaired Odda Smelteverk and Skaland Grafitverk from 1952, was a supervisory council member of Andresens Bank from 1959, and a board member of Automagnet/Robert Bosch Norge from 1948, Tyssefaldene from 1952, the Norwegian Branch of the International Law Association from 1952, Norsk Christiani & Nielsen from 1957, Kolberg Caspary from 1960 to 1970, Harald A. Møller from 1961, Norsk Marconikompani from 1963 and Borden Kjemi from 1966.