[1] Brynjel Andersen Gjerager was born in Voss in Hordaland, Norway.
In his home village, he served for many years a member of the Settlement Commission (forlikskommissaer) which mediated private disputes.
[2] [3] [4] He represented Søndre Bergenhus amt (now Hordaland) at the Norwegian Constituent Assembly at Eidsvoll in 1814.
He joined fellow representatives Georg Burchard Jersin and Arnoldus von Westen Sylow Koren.
At Eidsvoll, all three representatives supported the position of the independence party (Selvstendighetspartiet).