Niels was educated at Oxford University and began his career in the advertising and sponsorship industry, before moving into major events in the mid-1990s when he joined the British Government's planning team for the Millennium Celebrations and was responsible for generating record levels of commercial sponsorship.

Niels has 20 years of director level experience in the development and delivery of major international sporting events, dating back to when he joined the Organizing Committee of the 2002 Commonwealth Games in Manchester, England.

During his ten years as Chief Executive of UK Athletics, Niels also served as Chief Executive of the Organizing Committees for the IAAF World Cross Country Championships, IAAF World Half Marathon Championships, IAAF World Indoor Championships and IAAF World Athletics Championships in London. He was also heavily involved in the oversight of the 2012 London Olympics & Paralympics, as a Board member and Audit Chairman of The British Olympic Association (2009-2014).

In 2018 Niels left UK Athletics to set up a specialist consultancy (Fabric Group Ltd) to advise brands, cities and governments on better investments into art, sport, community and charity – the Fabric of Society.