NHØP started playing professionally in Copenhagen as a teenager, and by the time he was old enough to drink in most countries he was already the first-call bassist for visiting American musicians. Oscar Peterson heard him in the early 1960s and tried to hire him on the spot — NHØP ended up spending years as Peterson's regular bassist, which tells you everything about the level he was operating at.
What made him different was the combination of speed and warmth. A lot of bassists who can play fast end up sounding thin or mechanical. NHØP kept both: a big, woody tone that filled a room without amplification, moving across the strings at tempos that shouldn't have been possible on an acoustic instrument. He was also genuinely interested in solo bass — a strange, ambitious thing to pursue in an era when the instrument was almost exclusively a supporting role. You can hear that instinct on Double Bass (1976).
He was part of a generation of Scandinavian musicians who built a real jazz scene without being in New York, and the music that came out of it had its own character — a little more spacious, a little more lyrical, never soft. The Paris Concert: Salle Pleyel 1978 catches that in a live setting. His discography reads like a who's-who of jazz giants passing through Europe: Ben Webster, Bud Powell, Dizzy Gillespie.
He died in 2005 at 58 — too young, given how much ground he'd already covered. Full catalog on his artist page.