Campbell was starting his first tournament in more than five years and said he was "absolutely nervous on the first tee".
"I was surprised I hit the ball on the first tee. I'm relieved now that is all over. I'm full of gratitude that I'm here," he said.
"I'm just glad to be playing golf again. I didn't play great today and just managed to glue my round together. My driving was poor but beside that I am just glad to be here."
He said to shoot par was something to be pleased about but he was very surprised how nervous he was as he went to hit on the first tee on The Hills.
"You just have to use technique and tools that keep you nice and calm. So when I got to the ball itself I was OK but before that I was a bag of nerves.
"It was amazing though. The feelings of competing, playing in front of a crowd. It wasn't a great crowd but being involved just brings back the memories and thoughts from when I've previously been involved in this tournament."
Campbell (50) was handicapped in his driving and he said he lacked confidence with the club.
"Last night I was practising and my shaft split so I had to get a new shaft this morning, an emergency driver ... it just did not feel that comfortable."
He was impressed with how many other players went well under par.
"I'm not sure what the cut will be, could be three or four under. The pins were really tight today but that just shows how strong the Asian Tour, and Australasian tour and New Zealand golf is. Some of those pins today were pretty brutal."
He said the body had come through the 18 holes well and he enjoyed playing a competitive round again.
Campbell was steady throughout, mixing two birdies and two bogeys through his round. He bogeyed the 17th, three-putting the green, but made a nice approach on the 18th green after finding the fairway bunker.
He then calmly slotted a 3m putt to come away with an even 72 on The Hills.
Campbell was due to start at Millbrook today at 8.08am.
