At 34, the former Great Britain prop seemed to embody virtues that were just too old-fashioned to apply to the 1998 season. Instead, Harrison has led the way as Halifax have been one of the most consistent teams in the competition. Victory over Bradford at The Shay this evening will almost seal a top-three finish which few would have imagined for them at the start of the campaign.
"I did say before the season that, if we kept our senior players fit, we would definitely finish in the top five," Harrison said. "Well, we've kept them fit and we're going to do a bit better than that. People talk about our old players, but what it comes down to is having mentally tough people in the right areas of the field. There's only really me, Kelvin Skerrett and Gary Mercer who are getting on a bit. Apart from that, we're a young team."
For all that, it is the senior citizens in the pack upon whom Halifax's success has been built this season. Skerrett and Harrison have been intimidating presences in the front row, while Mercer has found a new lease of life behind them. "There were times last season when I was having to play the forwards on my own," Harrison added. "It's nice now that we've got Kelvin and players like young Richard Marshall and Des Clark to give me a rest occasionally.
"I also think that Gavin Clinch is an outstanding footballer at scrum- half - the sort of player we have been looking for there for a few years. Some Australians come here to take the money, but he has come to play. And Paul Rowley is a class player who has come on leaps and bounds this season. He used to be a bit short-sighted in his play, but now he's using his sharpness for the good of the team."
But this season's Halifax add up to more than the sum of their parts. "There's just a special feeling here," he said. "The closest thing I've known to it was at Hull when we beat Widnes to win the Premiership final. We weren't the best team in it and nobody rated us, but everything was just right. It feels very much the same this year."
The pleasure and the success that this campaign has brought have made Harrison, whose personal achievements include 14 Great Britain caps, think about extending his own playing career. "I'm 34, but I'm enjoying it so much that I'm seriously considering having another 12 months."
Whatever happens, he has already done much to disprove the theory that there is no place for the big, traditional-type prop in summer rugby. Halifax's approach has involved modifying the training regime for their senior citizens. "We don't train as hard as the others, but we do a lot of different stuff that puts less strain on the joints," Harrison said.
It is a system that has worked, as Bradford could find to their cost tonight, but Harrison regards the Bulls as dangerous opponents, despite their patchy form this year. "I think they've been very unfortunate, with injuries. James Lowes missed a lot of the pre-season and had never quite recovered," he said.
"But they're still a good side and they will be desperate to win this game. If we win, we're virtually guaranteed a top-three place, but it's more important to them than it is to us."