John Forbes Kerry (born December 11, 1943) is an American attorney, politician and diplomat currently serving as the first U.S. Special Presidential Envoy for Climate. A member of the Forbes family and the Democratic Party, he previously served as the 68th United States secretary of state from 2013 to 2017 in the administration of Barack Obama and represented Massachusetts in the United States Senate from 1985 to 2013. Kerry was the Democratic nominee for president of the United States in the 2004 election, losing to incumbent President George W. Bush.

Kerry grew up as a child of military personnel in Massachusetts and Washington, D.C., before attending boarding school in Massachusetts and New Hampshire. In 1966, after graduating from Yale University, he enlisted in the United States Naval Reserve, ultimately attaining the rank of lieutenant. From 1968 to 1969, during the Vietnam War, Kerry served an abbreviated four-month tour of duty in South Vietnam. While commanding a Swift boat, he sustained three wounds in combat with the Viet Cong, for which he earned three Purple Heart Medals. Kerry was awarded the Silver Star Medal and the Bronze Star Medal for valorous conduct in separate military engagements. After completing his active military service, Kerry returned to the United States and became an outspoken opponent of the Vietnam War. He gained national recognition as an anti-war activist, serving as a spokesperson for the Vietnam Veterans Against the War organization. Kerry testified in the Fulbright Hearings before the Senate Committee on Foreign Relations, where he described the United States government's policy in Vietnam as the cause of war crimes.

In 1972, Kerry entered electoral politics as a Democratic candidate for the United States House of Representatives in Massachusetts's 5th congressional district. Kerry won the Democratic nomination but was defeated in the general election by his Republican opponent. He subsequently worked as a radio talk show host in Lowell and as the executive director of an advocacy organization while attending the Boston College School of Law. After obtaining his juris doctor in 1976, Kerry served from 1977 to 1979 as the first assistant district attorney of Middlesex County, where he tried criminal cases and managed the district attorney's office. After a period in private legal practice, he was elected Lieutenant Governor of Massachusetts in 1982. In 1984, Kerry was elected to the United States Senate. As a member of the Senate Committee on Foreign Relations, he led a series of hearings investigating narcotics trafficking in Latin America, which exposed aspects of the Iran–Contra affair. He was reelected to additional terms in 1990, 1996, 2002 and 2008.

Kerry won the Democratic Party presidential nomination in 2004, alongside vice presidential nominee and North Carolina Senator John Edwards. Kerry campaigned as a critic of Republican President George W. Bush's prosecution of the Iraq War and advocated a liberal domestic policy. He lost the Electoral College and the popular vote by slim margins, winning 251 electors to Bush's 286 and 48.3% of the popular vote to Bush's 50.7%. Kerry remained in the Senate and chaired the Committee on Foreign Relations from 2009 to 2013.

In January 2013, Kerry was nominated by Obama to succeed Secretary of State Hillary Clinton, and was confirmed by his Senate colleagues on a vote of 94 to 3. He was U.S. secretary of state throughout the second term of the Obama administration from 2013 to 2017. During his tenure, he initiated the 2013–2014 Israeli–Palestinian peace talks and negotiated agreements restricting the nuclear program of Iran, including the 2013 Joint Plan of Action and the 2015 Joint Comprehensive Plan of Action. In 2015, Kerry signed the Paris Agreement on climate change on behalf of the United States.

At the end of the Obama administration in January 2017, Kerry remained active in public affairs from 2017 to 2021 as a vocal opponent of Obama's successor, President Donald Trump. Kerry returned to government in January 2021, becoming the first person to hold the new position of U.S. special presidential envoy for climate, under Joe Biden.