He was born in Bergen as the son of businessperson Johan Nordahl Wallem and his wife Emma Meltzer.
[1] Having a background as a seaman, he wrote and reported extensively about fisheries issues, both through newspapers, books and lectures.
Among other issues, he is credited with as the first describer of the purse seine in Norway, in 1877, long before it was actually introduced.
[1] In March 1877 he married Louise Adelaide Barbe, daughter of a French-American father and a German-American mother.
[1] Their son Fredrik Barbe Wallem became a notable art historian.