Beverley McLachlin had no career goal and little self-confidence when she went to university in the 1960s, let alone the faintest notion that she would one day become a role model to young women across the country.

More than 50 years later, perched on the threshold of legal history as the longest-serving chief justice of the Supreme Court of Canada, she says the symbolism of her gender is a constant source of astonishment.

In an interview to mark her passing the current record-holder – Sir William Johnstone Ritchie, chief justice from 1879 to 1892 – Chief Justice McLachlin says she is struck on Canada Day each year by the way parents who come to the court building introduce her to their children.

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"They want to show their children that we have a chief justice of Canada – and that she is a woman!" she says. "It shows an aspiration on the part of those parents and, in those shining children's eyes, of the fact that there aren't boundaries in this country in terms of gender.

"It has nothing to do with my personal qualities, of course," the 69-year-old judge adds. "It's just that I'm here."

In the interview, Chief Justice McLachlin reveals that she is determined to serve until her mandatory retirement at age 75, and that she worries deeply about the plight of the mentally ill in the justice system.

Skirting carefully around a contentious federal government policy, she says that the legal regime used to decide the fate of violent, mentally ill offenders has worked smoothly and "served us well."

Under reforms proposed by the federal government, it would become substantially more difficult for those designated as high-risk offenders to be reviewed and potentially released.

While the Chief Justice expresses reluctance to inject herself into a raging debate about a proposal to make the law more strict, she says she is unaware of any particular deficiencies in the current law. "Actually, my understanding is that it has worked quite well. Obviously, there are amendments being put forward and I'm not going to go into those, but it has served us well and it is looked at by other countries as a good model."

The Chief Justice's concern for the socially disadvantaged has been a constant in her long and productive judicial career, a trait that may spring from her humble background in small-town Alberta and her early sense of rootlessness.

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"I never had a plan," she recalls. "I didn't see any particular place where I would fulfill a role well and be happy,"

Worse still, high school counsellors painted a bleak picture involving few career options. "I had the lowest alertness level they had ever seen. They were scratching their heads: What can we do about this person who has a very high reading retention score, but not much else? I was a misfit. How was I going to make my way?"

The answer came in university. While studying for her BA in philosophy at the University of Alberta, she caught the eye of the dean of law. He encouraged her to follow up with a law degree. She rapidly discovered a love that has carried her to unfathomable heights.

Her ascension, she says, is "almost magical."

"I just cannot believe my good fortune. It is all astonishing to me how everything has worked out."

With good health and a boundless store of enthusiasm for her job, it seems certain that Chief Justice McLachlin will set longevity records. "I have no intention of stepping down or stepping aside," she says. "I'm loving my job and hope to continue on."

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Chief Justice McLachlin's judicial career began with an appointment to Vancouver County Court in 1981. She was soon elevated to the B.C. Supreme Court, the B.C. Court of Appeal and, in 1989, to the Supreme Court of Canada.

Just the third woman ever to sit on the top court, her total of 24 years on the Supreme Court bench has far surpassed the tenure of most judges.

In 2000, she took the reins of a court stocked with brilliant judges who were divided by factional infighting and intellectual schisms. She set about mending the court's image, ushering in a harmonious regime where ideas clash for the most part without harming personal relationships.

Surveys show that the court is held in high public esteem, and there is rarely any visible trace of rancour between the nine judges.

"Ideally, she would like to minimize controversy and leave a significant legacy," says Bruce Ryder, a constitutional law expert at York University's Osgoode Hall Law School. "She picks her battles accordingly. She works hard to forge a consensus on the court and often succeeds on big issues."

Former Supreme Court judge Marie Deschamps says the Chief Justice is personable, respectful and inclined to mediate. When judges are at odds with one another, she says Chief Justice McLachlin often asks them to meet face-to-face to work out their differences.

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"She does not have an emotional style," Ms. Deschamps says.

At the same time, the Chief Justice can be as firm with lawyers who stray from the point in court, as she is with judges who are slow to produce judgments. It stems from a desire for her court to be remembered for tackling cases efficiently and effectively.

"I would like this court to be thought of as one that produces high-calibre, wise jurisprudence; jurisprudence that works and makes Canada a better place," Chief Justice McLachlin says.

On a larger front, she has used her role as head of the Canadian Judicial Council to focus national attention on shortcomings such as affordable, accessible justice, says Mayo Moran, dean of law at the University of Toronto.

Her willingness to shine light on deficiencies in the court system, "has been vital in putting access to justice on the front burner and to prompting reform across a range of areas, including family law," Dean Moran says.

Chief Justice McLachlin declines to criticize the federal government for reducing the complement of female judges on the court from four to three. However, she affirms that gender parity is a vital goal.

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"When you get three or four women on a court of nine ... suddenly gender doesn't even become an issue," she observes. "It's amazing. You don't even think of the gender of the other person."

The reverse is equally true. "The fewer women that there are, the more I, as a woman, think: 'Oh, they are looking at me – she is deciding that because she is a woman,' " she says.

However, men and women are clearly a product of their different life experiences, she adds.

"There are myriad ways that society treats women differently than men, and men a little differently than women. We all bring our perspectives to our work. And perspectives are very important in judging."