From 2013 to 2015, he served as security coordinator for the 2015 Pacific Games, which were held in PNG's capital, Port Moresby in July of that year.
However, the Supreme Court of Papua New Guinea found that the position of head or secretary of the department of police had no constitutional and statutory foundation in law and thus Manning's appointment as commissioner was legal.
Controls on the sale of alcohol led to the death of a senior police officer in May 2020 when he intervened in a dispute between off-duty soldiers and a beer-shop owner.
This event seemed likely to lead to a confrontation between the police and the military and was only avoided by a joint intervention by Manning and Brigadier General Gilbert Toropo, head of the Royal Papua New Guinean armed forces.
Following the unrest in 2021 in neighbouring Solomon Islands, a contingent of PNG police was sent to the country as part of a Commonwealth peacekeeping force.