Nielsen was a prolific entrepreneur who started numerous companies. Just after ending his career he started a firm together with his wife, former actress
Rudi Nielsen, which imports Italian
leather works to
Scandinavia. Nielsen and Hansen met on the set of
Far til fire med fuld musik in 1961 and married in 1963. In the 1970s Nielsen became involved in professionalising
football in Denmark, and in 1977 he and later
Danish Minister of Science Helge Sander planned to found a professional Danish football league. As a consequence of these plans, Danish Football Association finally allowed professional football in Denmark from 1978. Harald Nielsen along with Alex Friedman founded – and became the first chairman of FC København A/S later
Parken Sport & Entertainment whose primary activity was the Danish club
FC København from 1992–1997, he stepped down from the board in 2007 and became the clubs first honorary member. He was Protektor for the Legends Club and until his death watched all the home matches of
FC København from Parken's A-stand. He was chairman and co-owner/founder of the largest
summer house building company in Denmark. He was president of the
Rebild National Park Society in 1997–2007. He led the Gunnar Nu Foundation for 18 years until 2009 and presided the distribution of over DKK 9 million to Danish sports in those years. On 26 October 2016, which would have been his 75th birthday, the square in front of Arena North, in Frederikshavn, was named the Harald Nielsens Plads in his honor. On 9 July 2018 an 8+ foot tall statue of Harald Nielsen in his youth was unveiled on his square, which is the largest statue of a footballer in Denmark. A prize is now given out each year called “Årets Guld-Harald” in his honor. ==Career statistics==