The appointment of Rudan follows the former Sydney FC defender's impressive NPL coaching record with Sydney United 58.
Rudan's role is slightly controversial as it was rumoured that Greenacre, after exceeding expectations in his third tenure as caretaker coach, would finally be given the permanent head coaching opportunity.
But Phoenix Chairman, Rob Morrison, believes Rudan's relative inexperience means he is the perfect fit for the struggling A-League club.
“We had a large number of successful coaches apply for the role, including a number with considerable A League experience but Mark stood out with his passion and desire to make a difference at the club," he said.
“The feedback on Mark from the people we spoke to, which included some of the most respected and experienced people in Australian football, was universally excellent with all stressing what a talented coach, man manager and determined leader he is.
Rudan won the 2013 National Premier League title with Sydney United, in addition to the 2016 NSW NPL title and two Waratah Cups. He was also assistant coach of the Australian U/21 side between 2016 and 2017.
“Mark is an exciting ‘next generation’ coach, who will bring fresh energy, focus and discipline to the playing group at the club and he can’t wait to stamp his mark upon the A-League.
“We are an ‘underdog’ club, we can’t escape that, we have to fight for everything we get and we wanted someone who would buy into what the club faces and is capable of leading that fight and we think Mark is that person."
Rudan said that the Nix were the perfect fit for his coaching philosophy. 
“I would like to place on record my thanks to the Wellington Phoenix Board for giving me this opportunity," he said.
“The Phoenix have a reputation for giving young Australian and New Zealand footballers their first starts in the Hyundai A League and now as a coach I have my first A League coaching opportunity. 
“There is huge potential at the Phoenix, already signed for the squad is a core group of experienced A League players as well as some of the most exciting young talents in the A league and we have the funding for some quality visa players ready to go. 
“The club has organised a great off-season with games in Asia and Australia already booked in.
“I couldn’t be more excited about the season ahead."