But in the battle for equity and the desire to leave a legacy with the days left of her illustrious career diminishing, the self-described "shy" Sinclair has become a fierce and vocal advocate for women's soccer.
"(I hope) I helped leave the sport in a better place than I found it," Sinclair said in Melbourne on Thursday on her legacy. "For so many years within the Canadian national team, our goal is to continue to move our sport forward.
"And along the way, hopefully inspire the next generation of young Canadians, girls, boys doesn't matter."
Mission accomplished for one of the most recognizable Canadian athletes, in any sport. The sheer number of No. 12 Sinclair jerseys - chosen because as a kid she was a fan of Toronto Blue Jays second baseman Roberto Alamar - in the crowd of any Canadian women's game is proof.
Sinclair will kick off a remarkable sixth World Cup when reigning Olympic champions Canada play Nigeria on Friday in Melbourne. A goal will make the Portland Thorns captain, the all-time leader in international goals with 190 in 323 appearances, the first player in history to score in six World Cups.
"It's hard to put words to Christine," said midfielder Sophie Schmidt, who plans to retire after the World Cup. "She's such a pivotal human being and player for this team. She's been the face of Canada Soccer for so many years.
"But it's been incredible to see her development as a captain and leader as well. She was more that quiet, lead-by-example player on the field and she still is. She's respected worldwide for that. She's just a class soccer player.
"She's also taken on the role of being that vocal leader and continuing to drive the sport specifically in Canada. She has such a powerful voice, and I think the beauty of it is she doesn't use it often. But when she does, it's extremely impactful."
SUPPORTING PAY PARITY
Sinclair - known affectionately as "Sinc" or "Sincy" to team mates - said her team's pay equity battle with Canada Soccer was all but resolved, and praised Janine Beckie, who is sidelined with a torn ACL, for handling negotiations so the players could focus on the tournament.
"It's about to get done," Sinclair said. "So honestly, we haven't thought about it for one second these past couple of weeks, just focusing on playing."
Canada's talismanic leader was sympathetic to Nigeria's own festering pay dispute.
"The world of women's football is very small, and we all support each other," Sinclair said. "I feel like each women's team has to face their battles and obviously this past year we've been facing ours, and Nigeria now, with their federation, so we fully support them.
"Every single player in this tournament deserves the world and deserves equal treatment from their federations."
The Women's World Cup is getting $150 million in prize money from FIFA, a threefold increase over 2019 but well shy of the $440 million the men received last year in Qatar.
"The women's game, it's got a long way to go to catch up to the men's game," Sinclair said. "It's new compared to the men's game. That being said, although our prize money continues to increase, we're nowhere near where it should be. It needs to be the exact same as a men's tournament . . . as players we expect that."
Sinclair also plays a huge and public role in fundraising efforts for Multiple Sclerosis, the disease her mom Sandra battled for nearly four decades before dying in 2022. MS also kept her mom from travelling to global tournaments such as the Olympics, from which Sinclair has two bronze medals and a gold.
Canada's victory in Tokyo 2020, Sinclair said, bears no weight on the World Cup, where her team hope to climb the World Cup podium for the first time.
"I mean, it's got a nice ring to it, not gonna lie," she laughed. "But it doesn't change a thing. Around the world, we're still overlooked, which is fine by us. We were overlooked heading into Tokyo and we showed the world what we're capable of. I think all it has done is helped us feel that confidence to know that we can beat any team in the world."
The seventh-ranked Canadians play the Republic of Ireland on July 26 and Australia on July 31.