Madam Halimah Yacob's father died when she was eight, and she spent her school years juggling studies with work to help her family get by.

Even so, she became the first in her family to enter university, then devoted four decades of her life to public service, speaking up for the vulnerable.

Yesterday, as she was sworn in as Singapore's eighth president, Prime Minister Lee Hsien Loong noted that her life story - from "hardship and deprivation" to success and giving back to society - reflects the Singapore story.

"Your life story symbolises the sort of society that we aspire to be, and reminds us that the Singapore story is one of hope and opportunity," he said during a speech at the Istana.

"In Singapore, no matter where we begin in life, if we work hard, we will have ample chances to do well. And when we make good, we have a responsibility in turn to help others around us."

Madam Halimah, in her speech, attributed this to meritocracy.

Her story is not an uncommon one in Singapore, she said, and similar stories have played out all over the island.

"We firmly believe that anyone who works hard should be able to realise his or her full potential, and make valuable contributions to society," she added. "I have strong personal convictions about our meritocratic system because without it, I would not be here today."

Recounting how her mother had brought her and her four siblings up single-handedly, Madam Halimah said they experienced poverty and hardship, struggling daily to survive.

"Fortunately, I was growing up in Singapore," she said.

Despite her family circumstances, a good education was within her reach as she had the support of family, teachers and the community, and also worked hard.

"That enabled me to launch my career in the public service, and later to give others in need a helping hand," she said.

That this is possible is something special and precious to the country, she added.

Her experiences are also an affirmation of Singapore's multiracialism, she said.

She grew up in Selegie House, in a multiracial neighbourhood, and attended the Singapore Chinese Girls' School, studying alongside classmates of all races.

In the unions, where she worked for over three decades, she helped workers regardless of their race.

When she became MP, she looked after the needs of Singaporeans of all races and religions.

The foundations of multiracialism were laid in Singapore's early years and have helped to build a diverse yet cohesive community, said Madam Halimah.

She noted that Singapore's founding fathers, including President Yusof Ishak, understood that multiracialism was not about ignoring or erasing differences between ethnic groups.

"Instead, they recognised our diversity and took steps to reassure every community that they were a unique and valued part of our society," she added.

She also said she was glad that multiracialism was not just enshrined in the national pledge, but also entrenched in key national policies like housing, education and security.

As a result, integration in housing and schools is now part of the social landscape, she said.

"Had we left them on their own, they might have taken a different direction."

But she added that every generation faces new challenges to the country's multiracialism.

"Every generation must update our institutions to strengthen our shared values. And every generation needs champions who care deeply about multiracialism and fight to uphold and realise this ideal," she said.

She pledged to be a President for all Singaporeans, regardless of race, language or religion.

Mr Lee said he had no doubt that Madam Halimah will unify all Singaporeans, like Mr Yusof did.

"You, too, will strengthen our sense of nationhood. You, too, will be our President," he said.