Niels, who was two years old when his father, Poul Due Jensen, established Grundfos in the basement of their home in Bjerringbro, Denmark, started an apprenticeship as an engine fitter in 1960, and later qualified as a mechanical engineer at Arhus Teknikum.
He took on his first management role at Grundfos in 1974, taking charge of Grundfos in 1977 following the death of his father.