Many would with reason, conclude that the Brown surname is in fact a German name. Braun after all is a long dated and historic family name from the Germanic states. However in this case, in so far as we have been able to research, the Brown name in this case is Norwegian.
Johan Johannessen Brown was born in Sogn og Fjordane in Norway in 1833. The use of a family name in Norway was unique around this time. It would be another 50 years before this practice became common. Little is known about the family origins and it is reasonable to assume that they may have been immigrants around that time as well into Norway. What is known however is that Johan Brown did immigrate to the US in 1860 and served an enlistment in the US Civil War. He died quite young in 1871 at age 37.