North football director Geoff Walsh announced at a press conference on Thursday that Harvey, who was set to become an unrestricted free agent at the end of this season, had re-signed with the Roos for 2015.
Sitting alongside Walsh at Arden Street on Thursday, Harvey told reporters he only thought about the potential 400-game milestone when it was mentioned in "every single interview" he did.
"I'm certainly not playing for 400 games, I'm playing to win a premiership, so if I look too far ahead I'll just play footy and I won't play good footy," Harvey said.
"I control what I've got control of now and that's playing some good footy and hopefully winning some games and if I do that [the rest] will take care of itself."
Harvey, 36, has played 378 games, equal fifth on the all-time League games list with Essendon great Simon Madden.
Despite his age, Harvey's re-signing comes as no surprise, with the veteran showing no signs that football old age is catching up with him.
Harvey is averaging a career-high 26.5 possessions a game this season and remains one of the Roos' biggest match-winners.
Harvey said he felt more like 30 than 36 and would play on as long as his body and mind were willing, and North coach Brad Scott thought he remained a valuable contributor to the team.
Walsh said there had been no sentiment in the Roos' decision to re-sign Harvey, who remained at "the top of his game".
"For North Melbourne people you continue to shake your head," Walsh said.
"History says that guys at 36 years of age don't continue to perform at the level he's performing at.
"To be in contention for All Australian honours and up there in awards – and I'm sure he'll poll well in our best and fairest – it's just a credit not only to his longevity but also the way he prepares and his passion.
"It's remarkable in a historical sense, but knowing Boomer no one is prepared to say that this is the last one-year deal.
"We might be back here again next year. In fact, I wouldn't be betting against it."
Next year, Harvey will become just the fifth player to stretch his career into a 20th League season, equalling the tallies of Tuck and Ted Whitten snr and behind only Fletcher (22) and Robert Harvey (21).
If he plays all six of North's remaining home and away games this year, he will climb past Robert Harvey (383 games) into fourth on the League's all-time games list, with only Michael Tuck (426), Kevin Bartlett (403) and Essendon defender Dustin Fletcher (391) ahead of him.
Harvey is already one of North's greatest players, having won a record five best and fairest awards, captaining the club from 2009-2012 and playing in the 1999 premiership.
He has also been named in the All Australian team four times (2000, 2005, 2007, 2008) and was joint runner-up in the 2007 Brownlow Medal.