"Truly honoured to have served the president for the last 4.5 years at the UN & excited to begin as @whitehouse National Security Advisor," Rice wrote on micro-blogging site Twitter to her nearly 3,00,000 followers. She is probably the first serving US national security advisor to have a Twitter account.
"Susan exemplifies the finest tradition of American diplomacy and leadership," Obama said on June 5 at the Rose Garden of the White House when he announced to appoint Rice for his top national security post.
"With her background as a scholar, Susan understands that there is no substitute for American leadership. She is at once passionate and pragmatic. I think everybody understands Susan is a fierce champion for justice and human dignity, but she's also mindful that we have to exercise our power wisely and deliberately," he said.
"Having served on the national security council staff herself, she knows how to bring people together around a common policy and then push it through to completion," Obama said.
"She knows our policies are stronger when we harness the views and talents of people across government. So Susan is the consummate public servant -- a patriot who puts her country first. She is fearless; she is tough," he said.
As the US ambassador to the UN, Obama said Rice had reinvigorated American diplomacy in New York. "She has helped to put in place tough sanctions on Iran and North Korea. She has defended Israel. She has stood up for innocent civilians, from Libya to Cote d’Ivoire. She has supported an independent South Sudan. She has raised her voice for human rights, including women’s rights," Obama said.
Rice is well known for advocating strong relationship with India. As the US ambassador to the UN, Rice maintained a close personal relationship with Hardeep Puri, the then Indian ambassador to the UN, when India was a member of the UN Security Council for two years.
Last August, she had travelled to India on a family vacation, during which she met top Indian officials including National Security Advisor Shivshankar Menon.
Image: Susan Rice replaces Tom Donilon in her new capacity as the NSA
Photograph: Spencer Platt/Getty Images
Susan Rice withdraws from race of US Secretary of State
'NSA bugs EU embassies, infiltrates their computer networks'
US bugged EU computer networks, offices: Report
US slaps espionage, theft charges on NSA whistleblower