Niven has more than 30 years of operational policing experience in the United Kingdom. He joined Strathclyde Police in 1985 serving throughout the west of Scotland in a variety of ranks and positions before progressing to the rank of Chief Superintendent. Niven previously held the role of President of the Association of Scottish Police Superintendents where he represented the interests of the operational leaders of policing in Scotland.
On leaving Police Scotland in 2016 Niven took up the position of Chief Executive Officer of South Ayrshire Escape from Homelessness (SeAscape).
Niven was appointed director of the Scottish Violence Reduction Unit in July 2018.