Dennis worked in journalism from age 17 until his death. He worked at newspapers in Weiser and Caldwell, Idaho; Baker city and Albany, Oregon, and Anderson, California. He then bought and ran the Intermountain News in Burney for many years. He branched out into real estate, becoming a licensed broker with his own agency. He also expanded on his lifelong interest in agriculture, buying a cattle ranch in Old Station and began raising purebred Brangus bulls.