Born 1926 in Copenhagen, Jacob Jensen left school early and joined his fathers upholstery workshop. Jensen joined the Copenhagen School of Arts and Crafts in 1948 as the only upholsterer among furniture makers, one of which was Poul Kjærholm. Training was based on the methods of Kaare Klint, taught by Hans J. Wegner and Jørn Utzon. Jensen graduated in 1952. Then there was only one design studio in Scandinavia, Bernadotte & Bjørn in Copenhagen, with Sigvard Bernadotte, son of the Swedish King, as partner. Jensen worked here from 1952 to 1958, as studio chief from 1954. It was Jensen who in 1955 designed the company's most known product, the Margrethe bowl, still in production.
In 1956, Jensen went to the USA to work for the design star Raymond Loewy in New York and Latham, Tyler & Jensen in Chicago. In 1960, Jensen became a partner in LTJ and managed the company's European interests until 1975.
In 1958, Jensen opened his own design studio in Copenhagen. He completed a Hi-Fi design concept for General Electric but they turned it down, so Jensen approached the small Danish firm Bang & Olufsen. Their relationship began in 1964 and continued until 1991. During this period, Jensen designed over 200 products for B&O, creating the form language which provided the company with its international status.
Jacob Jensen's design is exhibited in a number of museums around the world and includes a solo exhibition at MoMA in New York in 1978: "Bang & Olufsen - Design for Sound by Jacob Jensen".
Jensen is primarily known for his B&O designs but has designed more than 500 products. He has received over 70 design awards all over the world. In Denmark he has received the ID-award nine times, been awarded the Knights Cross of the Order of Dannebrog and is on the Foreign Ministry's list of "Great Danes".
In 1990, Timothy Jacob Jensen, his son, took over the company. Jacob Jensen died at the age of 89 on 15 May 2015.