Kaiser was born in Portland, Oregon, on July 5, 1942, and was the grandson of shipbuilding industrialist Henry J. Kaiser.

Kaiser purchased the Broncos from the Gerald Phipps’ family in February 1981. He sold his 60.8% share of the Broncos to late owner Pat Bowlen in March 1984. He then sued Bowlen for violating the original sales’ agreement, which he contended granted him right of first purchase of any sale of shares in the team. Kaiser claimed Bowlen violated this agreement by offering former Broncos quarterback John Elway a 10% stake of the company that holds ownership of the team. In 2004, a jury ruled in favor of Kaiser, and a federal judge decreed that Kaiser was entitled to purchase back 10% of the Broncos using the identical purchase terms offered to Elway. Bowlen appealed the original verdict that ruled in favor of Kaiser and won the appeal, as the appellate court ruled that the structure of the Bowlen-Elway deal did not violate the original agreement.

In 1985, Edgar Kaiser Jr. established the Kaiser Foundation. It is a North Vancouver, British Columbia-based organization established as a Canadian national organization, operated separately from other ventures of the Kaiser family, with the goal of promoting the understanding and importance of mental health and addictions as health issues. It has also established the Kaiser Mental Health and Addictions Awareness Foundation and the Aboriginal Peoples’ Health Initiative.