Jenssen bought his first synthesizer in the early 80s while studying archaeology at university and put out his first album, Likvider, on cassette in 1984. It was credited to E-man. Jenssen then joined the synth trio, Bel Canto, and continued his solo productions up to 1990, releasing a number of 12“ records and an album, The North Pole by Submarine, under the moniker Bleep.

The first material penned under the name Biosphere was the full-length, Microgravity, which appeared in 1991 on the Norwegian Origo Sound label, and was picked up for international release by R&S subsidiary Apollo the following year. Substrata (All Saints Records, 1997) was the first intensely minimal Biosphere album and often considered not only his finest work, but one of the early classics of ambient electronica. In 2001, he received the Norwegian Grammy for the album Cirque.

Jenssen is an enthusiastic mountain climber and cites the landscape as an inspiration for his music. He often combines field recordings from various climbs with soundscapes and bass drones, evoking associations with northern landscape imagery.