Interview: Professor Louise Richardson, principal of St Andrews University

She is speaking from experience. Having to care for her own young children at the same time as working resulted in what she describes as one of the worst moments of her life.

She was a junior lecturer in political science at Harvard and had two young daughters. When her second daughter Fiona was about six weeks old, Richardson had to present a paper at a conference in Washington and took her baby and her two-year-old with her.

"There were about 5000 people at this massive conference and I remember standing there with my briefcase in one hand, Fiona under my arm and Ciara standing there," she explains. "Then the lift opened, Ciara ran in and the door closed." She closes her eyes and exhales.

"I will never forget. I called security and they couldn't stop the lift but they got somebody onto it. It was a massive hotel, 25 floors, so she was gone a long time. When the door finally opened, she was howling. All these people were coming over and saying, 'What kind of mother are you? She's much too young to be left on her own in a lift.' And I'm standing there thinking: 'You think I planned it like that?'"

The memory makes Richardson visibly shiver still, 21 years on, but she is also unimpressed by how little practical support was available to her as a working mum. In her first year of teaching, the demands of childcare and preparing two lectures a week meant Richardson did not sleep at all on Monday or Wednesday nights. At Harvard, she spent more on daycare than she earned. When her working day ended at 5pm, she sometimes had to take her daughter to faculty meetings, where she was the only woman.

"Everybody was very embarrassed by what I was doing so nobody acknowledged it. Someone would say, So Louise what do you think of Clause 5, subsection D?, and I would think oh God, that's the one Ciara's eating under the table."

It is a tough time for women and shouldn't be, she concludes. Yet is certainly hasn't held her back. Her illustrious career has led here, to the small but meticulously tidy wood-panelled principal's office in a medieval building on North Street, St Andrews. She swept in from an earlier appointment 10 minutes ago, posed for photographs in the quad and is now answering questions with a disarming directness that chimes with her businesslike demeanour.

Richardson, 54, was executive dean of the Radcliffe Institute for Advanced Study at Harvard before becoming St Andrews' principal and vice-chancellor in 2009. She was also known as one of the world's leading authorities on terrorism. Irish by birth, she studied history at Trinity College, Dublin, before completing an MA in political science at the University of California which led to offers of scholarships from Yale, Princeton and Harvard. She chose the latter and, after gaining an MA and doctorate in government, joined the staff there in 1989.

She progressed quickly and in 2006 wrote the much-respected What Terrorists Want: Understanding the Enemy, Containing the Threat. It was an impressive rise for the girl from small-town Ireland – but then she was a very self-confident child.

One of seven and the oldest girl, Richardson grew up in Tramore, County Waterford, a seaside town on Ireland's south-east coast. "I was related to most people through my mother's side," she says, her Irish accent still strong except for the occasional flash of American pronunciation. "My mother used to say that at the age of two I'd speak to her with plenty of self-confidence. It's a great asset to grow up with some self-confidence."

She was by her own reckoning "a bit of a trouble-maker" at her state convent schools, first at Tramore and then in Waterford, becoming "very political" at secondary school. Northern Ireland was "exploding" and she was powerfully moved by the Irish nationalist cause, which was what sparked her lifelong interest in terrorism. Much of this she attributes to music, as she would listen to Irish nationalist songs on the radio while in the car with her parents and siblings.

"I learned every rebel song by heart," she says. "I had a highly oversimplified view of Irish history as the good Irish against the bad English, a tale of woe and oppression. I have copies of poems I wrote as a child, ghastly anti-English poems, and I have to say the history we were taught in schools then reinforced it."

Trinity College was the seat of learning of the Irish Protestant aristocracy and the Church forbade Catholics from attending until 1970. Richardson was one of only three Catholics in her cohort. She announced to her mother and sales-rep father she would work to pay her own fees and was as good as her word, doing two jobs during term time, in the library and as a cocktail waitress.

SHE had not lost her pro-nationalist sympathies and while at Trinity was recruited to Sinn Fein's Republican Club. "I was very sympathetic to their ends but objected to their means, so I used to go along to meetings and we would debate this." She moved on to other causes, notably against apartheid, but her interest in the sort of people attracted to terrorist causes – "young idealists, people who wanted to sacrifice themselves for a good cause" – remained.

Heading to California on the day of her last exam at Trinity to escape "the smallness" of Irish life, she fell in love with classless America. Though her initial area of study was American foreign policy and international security, she read a lot about terrorism and became frustrated by what she encountered. "I felt there was a very undifferentiated, oversimplified view of terrorists. They were seen as one-dimensional bad guys and I thought it was much more complex than that."

Is Islamic terrorism, as it currently manifests itself, a passing phase of history? "Yes, yes, in essence. I thought David Cameron's speech in which he described Islamic terrorism in north Africa as 'an existential threat' was really a mistake. I don't think terrorism poses an existential threat, I don't think it ever has, I don't think it ever will. We have to keep the threat in perspective and not exaggerate it, which we're prone to do. It plays right into the terrorists' hands."

Richardson met her American husband Tom, a family doctor, when she was a graduate student, and the couple now have three children: Ciara is 23, Fiona 21, and Rory 18. The plan when she moved to Scotland was that the whole family would join her within six months but it hasn't worked out that way. Richardson came over with her son, then 14, but he was unhappy and "fled home" after six months. Rory is now at university in Aberdeen, Fiona is at Harvard and Ciara is doing a master's degree in Paris; Tom is still working in the US. "So now we commute across the Atlantic," she says, as if describing a bus ride to Dundee.

"We have a six-week rule – we have to see each other no less frequently than every six weeks and we usually manage to do more than that." When she has spare time, she reads a lot of fiction and loves exercise (though she doesn't play golf and still hasn't been offered honorary membership of the men-only Royal and Ancient).

As part of the St Andrews 600th anniversary celebrations this year, she is part of a cycle relay team, retracing a section of the route of the papal bull carried from Pensicola in Spain to St Andrews in 1413 to establish the university. The occasion has boosted the rate of alumni donations, which is an area she hopes to develop further.

With most of her family still firmly on the other side of the Atlantic, she surely doesn't feel very settled? "I don't think I've ever felt settled in my life," she admits, but adds with a smile: "I'm very happy here."

Louise Richardson

Principal of University of St Andrews