Jensen was a founder and the first president of the
Norwegian Postal History Society, served as president of the
Norwegian Philatelic Federation and the
FIP Postal History Commission. He was also named vice president of the Norwegian philatelic exhibition NORWEX 1980 and later secretary general of NORWEX 1997. Along with Patrick Pearson and
Robert P. Odenweller, Jensen was co-author of the
F.I.P. Guide to Exhibiting and Judging Traditional and Postal History Exhibits, published in 1993. Jensen was also a noted speaker on philatelic subjects, and dedicated efforts to introduce youth into the hobby of stamp collecting. ==Honors and awards==