McGinn said it was an easy decision to bring back Witcombe.
"We wanted him to return the 'mighty' to the Taniwha. He was the outstanding candidate out of the 26 applicants and he was a huge success in his last tenure," he said.
"Derren will bring a defined edge and experience at Mitre 10 Cup level. He will work very well with the assistant coach Dale McLeod."
McGinn said the expectations on Witcombe are gaining a semifinal berth and bringing back an exciting running rugby game plan.
As a player Witcombe achieved at the highest levels. He is All Black number 1053, playing five test matches. He also played 53 games for the Blues, 30 for Auckland in the NPC and 20 for Northland.
For the past two years Witcombe has been coaching in Japan as the assistant coach for the Mitsubishi Dynaboars in the Japan Top East Competition.
Witcombe is currently completing his coaching duties in Japan and will commence with Northland from April 1.
McLeod was reappointed his role as assistant coach after holding the position during the 2015 and 2016 seasons.
Along with his role at Northland, McLeod was the Blues 'A' assistant coach to Steve Jackson through their unbeaten 2016 season and will take the reins of the Blues 'A' team as head coach in 2017.
He has been a NZ Under-20 selector for five years.
McGinn was recently officially appointed the CEO for Northland Rugby.
He said he had a lot to offer in his new role.
"I want to bring strong management direction and clear vision to the core objectives of the Northland Rugby Union," he said.
"Growth and development of community and high performance playing numbers as well as the strength of playing standards are my main objectives as CEO."