[1] [2] Jaabech was born in Usland at Øyslebø in Vest-Agder, Norway.
He was the son of Haagen Olson Usland (1721–1773) and Marte Eriksdtr.
In 1806, he bought the farm Jaabekk in Halse parish (Jåbekk gård i Halse ved Mandal) and established residence at that farm.
[4][5] He was elected to the Norwegian Constituent Assembly in 1814, representing the constituency of Mandals Amt (now Vest-Agder) together with Osmund Andersen Lømsland and Syvert Omundsen Eeg.
At the Assembly, all three supported the union party (unionspartiet).