The 48-year-old's Moneyfields departure was confirmed and his arrival as the Royals' new manager announced all in the space of a few hours today.
Carter takes over at Portchester with the challenge of getting the club out of the Wessex League Premier Division for the first time.
It's a task the former Moneys manager, who is dropping down a division to take the role, is familiar with having won promotion to the Southern League at the end of his first full season at Dover Road in 2017.
And Carter revealed trying to achieve the feat of getting another team out of the Wessex League was a major factor behind his decision to move to The Crest Finance Stadium.
‘I just needed a new challenge in my life,' he said.
‘They (Portchester) approached Moneyfields to talk to me, I spoke to them, and liked what they had to say.
‘It’s a division I know - I’ve not been in there the past four years, but I watch a lot of games when we’re not playing.
'They’ve (Portchester) got a great set up off the pitch, probably one of the best in the area, and they know they just need to get it right on it.
‘They sold me the dream. Me and Gav (Spurway; assistant manager) have both been and met them, we both want to push on, take it on and see if we can push them into the Southern League and beyond.
‘I believe in my own ability and opinion that I can go there and get them out in the first season.'
Carter made it clear he departed Moneyfields after a six-year association on good terms.
He insists it's a club that remains 'close to his heart' and provided him with some 'great' memories.
Carter said: ‘Going forward for them (Moneyfields), I felt that they needed - the chairman said they wanted to keep me - they’ve got a lot of changes going on at Moneyfields which will be for the better in the long run.
‘But I’m getting to the stage in my football career where I’ve only got a few years left.
‘I appreciate everything Moneyfields have done for me, I’ve had some great memories in the last six years there with all the lads and that.
‘Moneyfields is close to my heart, I was there six years, it’s a long time.
‘I wanted to give them the best opportunity to get the right person in that they need to and what they need to do.'
Portchester chairman Paul Kelly adopted a patient approach in looking for a replacement after sacking Mick Catlin in October after a poor start to 2020/21 after a major summer of squad rebuilding.
Marty Wallace had been in interim charge prior to the season suspension last month.
But Kelly believes the club have now get the best person to 'take them forward' given Carter's impressive track record in the Wessex League with Horndean and Moneyfields.
The Royals chairman said: ‘I’m really pleased.
‘We took our time in appointing somebody but we feel this is the right decision for the club at this moment in time.
‘No doubt, with Dave’s past record at Horndean and Moneyfields, he’ll be the person to take us forward.
'There’s no secret of how ambitious we are and Dave shares those ambitions.
‘We just feel this is the right time to make this appointment and take us forward so happy days.'
Carter’s departure ends a Moneys career that began in October 2015 when he left Horndean to replace Miles Rutherford, who had left to take over at Chichester City.