Schmirler was born to parents Shirley and Art Schmirler on June 11, 1963. She was born with a club foot, which required her to wear a cast for two months. She had two older sisters, Carol and Beverley. She attended high school in Biggar, and moved to Saskatoon to attend university. She started out towards a degree in computer science, but transferred after her first year to work for a degree in physical education. She convocated with a Bachelor of Science in Physical Education in 1985.

While attending Biggar Composite School in Biggar, Saskatchewan, Canada, Schmirler started curling in Grade 7 as part of the school’s physical education program. She grew up an athlete, playing volleyball, badminton, and softball. She was also an avid speed swimmer. She continued to curl on the local scene, participating in the Biggar Curling Club ladies’ league in Grade 9. Playing as third on her high school team, she won a provincial championship in Grade 12, when her team went undefeated throughout the season. She continued to curl after graduating from high school, while attending the University of Saskatchewan. While in university, Schmirler made her first appearance in Saskatchewan’s provincial playdowns in 1983. Schmirler threw fourth stones for a team which consisted of 1979 Canadian Junior Champions Denise Wilson (skip), Dianne Choquette and Shannon Olafson. The team represented the University of Saskatchewan at the Saskatoon city playdowns where they were eliminated. After graduating university, Schmirler moved to Regina to take a job at the North West Leisure Centre. She continued to curl, and was given the nickname “Schmirler the Curler” by a supervisor at the facility. Schmirler joined the Saskatoon-based Carol Davis rink, playing third for the team. In their first season together, they made it to the 1984 provincial finals where they lost to Lori McGeary.

In 1987, as a member of Kathy Fahlman’s rink, Schmirler won her first provincial championship, sending her to her first national championship, where she and her team finished in fourth place with a 7–5 win-loss record. The following season, the team lost in the A-B final of the 1988 provincials to Michelle Schneider (now Englot), eliminating them from a chance at a second straight trip to the Hearts. In the 1989 playdowns, Team Fahlman lost in the southern Saskatchewan playdowns, failing to even make it to the 1989 Saskatchewan Scott Tournament of Hearts.

Prior to the 1988–89 curling season, Schmirler and Jan Betker found themselves curling with different teammates, attempting to put together a stable squad. After a disappointing season, Schmirler decided to skip for the 1990–91 season, with Betker playing third. They recruited Joan Inglis (McCusker) to play second, and McCusker recommended Marcia Gudereit as a lead. This rink won the provincials in their first year together and finished in fourth place at the Scott Tournament of Hearts. In 1993, the Schmirler rink again won the provincial title to move on to the Tournament of Hearts. Her rink defeated Maureen Bonar in the finals, giving Saskatchewan its first national women’s curling championship since Marj Mitchell’s win in 1980. The rink moved on to the World Championship and defeated Janet Clews-Strayer from Germany in the final that year, winning Canada its sixth world women’s title. The next season, she and her rink competed at the Tournament of Hearts as defending champions. The team finished first in the round robin, and defeated Connie Laliberte in the final to clinch a second consecutive Canadian championship. She and her team then represented Canada at the World Women’s Curling Championship, where they finished first in the round robin. She then advanced to the playoffs, and won the semifinal against Josefine Einsle of Germany and the final against Christine Cannon of Scotland. With her win in the final, she and her team clinched their second world championships, equalling their run from the previous season. At the time, no other Canadian women’s rink had won consecutive world championships. Schmirler returned to the Tournament of Hearts the next year as the defending champion. She and her team finished with an 8–3 win-loss record and advanced to the playoffs as the second seed. She lost her next two games, however, and failed to advance to the final, losing a chance to win a third consecutive title. The next season, Schmirler added Renelle Bryden to the lineup, as McCusker took the year off. For the 1996 Saskatchewan Tournament of Hearts, Gudereit who had been playing second was replaced for health reasons by Karen Daku. At the provincial Hearts, the team fell to Sherry Scheirich (now Middaugh) in the final.

In 1993, teammate Marcia Gudereit introduced Schmirler to Shannon England. On June 22, 1996, they were married. In 1997, Schmirler was pregnant with their first child. When this information was revealed to reporters at the Scott Tournament of Hearts, they jokingly dubbed her “Schmirler the Hurler”. On September 15, 1997, their daughter Sara Marion was born. In April 1999, Sandra’s father Art Schmirler died from esophageal cancer. On June 30, 1999, the couple’s second daughter, Jenna Shirley, was born.

In 1997, Schmirler and her rink returned to the Tournament of Hearts, where they finished with a 9–2 win-loss record in the round robin. They advanced to the playoffs, and defeated Alison Goring of Ontario twice en route to winning her third Canadian championship. They then went to the World Championships, where they again finished first in the round robin and advanced to the playoffs, defeating Helena Blach Lavrsen of Denmark in the semifinals and Andrea Schöpp of Germany in the final to win a third world title. After each of these three seasons, her rink was named “Team of the Year” by Sask Sport.

In the 1998 Winter Olympics, curling became a medal sport for the first time. Olympic trials were held in November 1997 to select Canada’s representatives at the Olympics. The Schmirler rink finished first in the round robin, and defeated Shannon Kleibrink in the final with a score of 9–6, behind strong shot making from Schmirler and McCusker. Schmirler made a difficult in-off to win and clinch the berth to the Olympics. The 1998 Winter Olympics were held in Nagano, Japan. The Schmirler rink was among the favourites for gold, but there was a strong field in the event. After finishing the round robin in first place with six wins and one loss, Canada played their semifinal game against Great Britain’s Kirsty Hay. The game was tied after regulation play and went to an extra end, where Schmirler barely made a draw with her last rock to win the game. In the final against Denmark’s Helena Blach Lavrsen, Schmirler secured a win in nine ends, winning Canada the gold medal. After winning the gold medal, Sandra appeared on the front page of The New York Times. After the Olympics, the Schmirler rink was named ‘Team of the Year’ by the Canadian Press. The team were also inducted into the Canadian Curling Hall of Fame in 1999. After returning from the Olympics, Schmirler and her rink had to compete almost immediately in the Scott Tournament of Hearts as Team Canada. Schmirler and her team made the playoffs, and won the 3 vs. 4 playoff game before dropping the semifinal to Anne Merklinger. After losing in the semis, Schmirler joined CBC as a colour commentator for the final match.

After Jenna’s birth, Schmirler experienced many health problems. She had suffered from back pain, which was thought to be pregnancy related, and following Jenna’s birth, she began to suffer from stomach pains. Tests showed that a cancerous node the size of a fist had developed behind her heart. As her condition worsened, she underwent surgery on September 6, 1999. During surgery, a dead piece of the tumour broke off and released a blood clot into her lung. Her heart stopped beating, and only emergency heart massage kept her alive. Almost a month after being diagnosed with cancer, doctors finally provided a specific diagnosis – metastatic adenocarcinoma, with an unknown primary site. Because no one could pin down where the cancer came from, Sandra referred to it as “the cancer from Mars.” In addition to chemotherapy and radiation, Schmirler explored orthomolecular medicine through the Canadian Cancer Research Group. This form of alternative medicine involves large doses of vitamins and nutrients.

In 2000, Schmirler worked as colour commentator for CBC during Canada’s national junior curling championships. During her illness, Schmirler had been largely removed from the public eye. While in Moncton for the championships, Schmirler held a press conference to update her situation. In speaking publicly about her ordeal for the first time, Schmirler spared few details about what she had gone through, while also expressing her hope for the future: “There were three goals I had coming out of this thing, and the first one was to look after my family. And the second one…because I curl so much, I’ve never taken a hot vacation, so I’m going to put my feet in the sand in a warm place. And the last one was to actually be here today, and I thank CBC, I thank Lawrence (Kimber), and Joan Mead.”

In addition to the titles captured by her team on the ice, Schmirler has been recognized in several different ways off the ice as well. In 2000, Schmirler was awarded the Saskatchewan Order of Merit, becoming the first posthumous recipient. Along with the other members of her rink, she had been previously awarded an honorary Doctor of Laws degree from the University of Regina. In the fall of 2000, Schmirler was inducted into the Canadian Sports Hall of Fame. Schmirler and her team were inducted into the Saskatchewan Sports Hall of Fame on two separate occasions, once in 1997 for winning three World Curling Championships and once in 2001 for winning the gold medal at the Olympics. At the annual Scotties Tournament of Hearts, the top player in the playoff round is awarded the Sandra Schmirler Most Valuable Player Award.

After returning from Moncton, Schmirler felt physically well, but suffered a setback when a CAT scan revealed spots around her lungs. The decision was made not to proceed with further chemotherapy, but she continued with the orthomolecular therapy. She had been scheduled to work the 2000 Scott Tournament of Hearts, but was unable to do so. She faxed a statement from the hospital, which was read by TSN’s Vic Rauter. “I’m still fighting hard and I still hope to make it to the Brier, not playing but talking. For Saskatchewan, I was hoping to be in your green shoes (at the Scott). But keep things in perspective. There are other things in life besides curling, which I have found. But I hope to be on the curling trail again next year. And I’ll see you all in Sudbury (the next Scott site) in 2001. Your curling friend, Sandra.” However, the optimism in her statement belied the seriousness of her condition. She had been moved to palliative care. She died in her sleep at the Pasqua Hospital Palliative Care Unit on the morning of March 2, 2000 at age 36.

“The Sandra Schmirler Foundation was created in May 2001 by a group of Sandra’s friends and teammates. Their vision was to create a living legacy in honour of this amazing woman who touched the hearts of so many Canadians from coast to coast to coast. While she lost her biggest battle, her legacy lives on. The lives of countless babies born premature and critically ill have been, and continue to be saved, with life-saving equipment the Foundation has funded in her name. Millions of dollars have been given to hospital NICUs in every province, the Yukon and Northwest Territories to fund life-saving equipment for babies born too soon, too small or too sick. This list continues to grow every year with the generous support of our many donors. Sandra reached out to her country in sickness and in health and made us understand what really matters in life. While we mourn her passing, we celebrate the lasting legacy she left behind.” Robin Wilson

On January 7, 2009, Sandra was named the winner of the 2009 World Curling Freytag Award (later incorporated into the WCF Hall of Fame). The award, named after American Elmer Freytag, who founded the World Curling Federation, honours curlers for championship play, sportsmanship, character and extraordinary achievement. Her husband and daughters accepted the award on her behalf at the 2009 World Men’s Curling Championship.