Ruan views Kerry as professional, calm and pragmatic, and expects him to initiate strategic dialogues between China and the US, which will wield positive influence on Sino-US relations.

As the new secretary of state, and a supporter of the Asian rebalancing strategy, Kerry would be less aggressive than his predecessor Clinton, said Jin Canrong, an international affairs professor at Renmin University of China.

In an era when being secretary of state is increasingly about style as much as substance, many foreign-policy experts said the five-term senator and quiet negotiator is expected to return the office to a more traditional version of diplomacy, according to The Christian Science Monitor.

The Vietnam veteran, who was critical of the war after he returned home, lost to US president George W Bush in the 2004 election.

He has represented Massachusetts in the senate since 1985, and has served as chairman of the Senate Foreign Relations Committee for decades.

During his first term, Obama sent Kerry around the world on his behalf numerous times, particularly to Afghanistan and Pakistan.

He also helped prepare the president for his live TV debates during this year's election, and won praise from Obama for his sharp national security-focused speech at the Democratic National Convention in August, when he told delegates: "Ask Osama bin Laden if he's better off now than he was four years ago."

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