Henry Kissinger, the diplomatic powerhouse whose service under two presidents left a lifelong mark on US foreign policy, has died at the age of 100.

The diplomat, best known for his time as Secretary of State to Richard Nixon, continued to be closely involved in global foreign policy past his hundredth birthday – visiting Xi Jinping in Beijing in July this year.

“Dr. Henry Kissinger, a respected American scholar and statesman, died today at his home in Connecticut,” his consultancy Kissinger Associates said in a statement on Wednesday.

Although his foreign policy decisions and their association with the doctrine of “realism” were controversial, he survived the resignation of Mr Nixon in 1974 and continued to offer advice in that post to his successor, Gerald Ford.

His 1973 Peace Prize - awarded jointly to North Vietnam’s Le Duc Tho, who would decline it - was one of the most controversial ever. Two members of the Nobel committee resigned over the selection and questions arose about the US secret bombing of Cambodia.

Serving first as National Security Adviser to the Nixon administration, Mr Kissinger was closely associated with the US policy of “Vietnamisation” in the 1970s, as the burden of the war transferred from American troops to Southern Vietnamese forces.

He was given the role of Secretary of State in 1973, serving for one year before becoming an informal adviser to presidents on foreign policy and running his own geopolitical consulting firm in New York City from 1982.

His influence in government waned under the next Republican president, Ronald Reagan, and he moved to international speaking events, private work and writing more than a dozen books.

He was invited to the White House to speak with every president after Mr Ford, apart from Joe Biden, and celebrated his 100th birthday in May.

Although influential, Mr Kissinger’s legacy was controversial and he invited criticism from opponents of his policy on Vietnam, the bombing of Cambodia and the invasion of Timor-Leste in 1975.

In the India-Pakistan War of 1971, Mr Nixon and Mr Kissinger were heavily criticised for tilting toward Pakistan.

Mr Kissinger was heard calling the Indians “bastards” - a remark he later said he regretted.

Anthony Bourdain, the late food critic, once said: “Once you’ve been to Cambodia, you’ll never stop wanting to beat Henry Kissinger to death with your bare hands.”

Christopher Hitchens, the British polemicist, dedicated an entire book to his legacy entitled The Trial of Henry Kissinger.

Nonetheless, the German-born Jewish refugee’s efforts led to the diplomatic opening of China, landmark US-Soviet arms control talks, expanded ties between Israel and its Arab neighbours, and the Paris Peace Accords with North Vietnam.

After the 9/11 attacks, President George W Bush picked Kissinger to head an investigative committee.

Outcry from Democrats who saw a conflict of interest with many of his consulting firm’s clients forced him to step down from the post.