When Yuri Andropov succeeded Leonid Brezhnev as leader of the Soviet Union in November 1982, the mainstream Western newspapers and magazines ran numerous front page photographs and articles about him. Most coverage was negative and tended to a perception of a new threat to the stability of the Western world. Andropov had been the Soviet Ambassador to Hungary during the 1956 Hungarian Revolution and began his tenure as Soviet leader by strengthening the powers of the KGB, and by suppressing dissidents. Andropov declared, "the struggle for human rights was a part of a wide-ranging imperialist plot to undermine the foundation of the Soviet state." Much international tension surrounded both Soviet and American efforts to develop weapons capable of being launched from satellites in orbit. Both governments had extensive research and development programs to develop such technology. However, both nations were coming under increasing pressure to disband the project. In America, president Ronald Reagan came under pressure from a lobby of U.S. scientists and arms experts, while in Russia the government issued a statement that read, "To prevent the militarization of space is one of the most urgent tasks facing mankind".

During this period, large anti-nuclear protests were taking place across Europe and North America, while the November 20, 1983, screening of ABC's post-nuclear war dramatization The Day After became one of the most anticipated media events of the decade.

The two superpowers had by this point abandoned their strategy of détente and in response to the Soviet deployment of SS-20s, Reagan moved to deploy cruise and Pershing II missiles to Europe. The Soviet Union's involvement in a war in Afghanistan was in its third year, a matter which was also contributing to international tension. In this atmosphere, on November 22, 1982, Time magazine published an issue with Andropov on the cover. When Smith viewed the edition, she asked her mother, "If people are so afraid of him, why doesn't someone write a letter asking whether he wants to have a war or not?" Her mother replied, "Why don't you?"

Samantha Smith was born on June 29, 1972, in the small town of Houlton, Maine, on the Canada—United States border, to Jane Reed and Arthur Smith. At the age of five, she wrote a letter to Queen Elizabeth II to express her admiration to the monarch. When Smith had finished second grade in spring 1980, the family settled in Manchester, Maine, where she attended Manchester Elementary School. Her father taught literature and writing at the University of Maine at Augusta while her mother worked as a social worker with the Maine Department of Human Services.

In November 1982, when Smith was 10 years old, she wrote to Soviet leader Yuri Andropov, seeking to understand why the relations between the Soviet Union and the United States were so tense:

Dear Mr. Andropov,

My name is Samantha Smith. I am ten years old. Congratulations on your new job. I have been worrying about Russia and the United States getting into a nuclear war. Are you going to vote to have a war or not? If you aren't please tell me how you are going to help to not have a war. This question you do not have to answer, but I would like to know why you want to conquer the world or at least our country. God made the world for us to live together in peace and not to fight.

Sincerely,

"Samantha Smith"

Her letter was published in the Soviet newspaper Pravda.Samantha was happy to discover that her letter had been published; however, she had not received a reply. She then sent a letter to the Soviet Union's Ambassador to the United States asking if Mr. Andropov intended to respond. On April 26, 1983, she received a response from Andropov:

Dear Samantha,

I received your letter, which is like many others that have reached me recently from your country and from other countries around the world.

It seems to me — I can tell by your letter — that you are a courageous and honest girl, resembling Becky, the friend of Tom Sawyer in the famous book of your compatriot Mark Twain. This book is well known and loved in our country by all boys and girls.

You write that you are anxious about whether there will be a nuclear war between our two countries. And you ask are we doing anything so that war will not break out.

Your question is the most important of those that every thinking man can pose. I will reply to you seriously and honestly.

Yes, Samantha, we in the Soviet Union are trying to do everything so that there will not be war on Earth. This is what every Soviet man wants. This is what the great founder of our state, Vladimir Lenin, taught us.

Soviet people well know what a terrible thing war is. Forty-two years ago, Nazi Germany, which strove for supremacy over the whole world, attacked our country, burned and destroyed many thousands of our towns and villages, killed millions of Soviet men, women and children.

In that war, which ended with our victory, we were in alliance with the United States: together we fought for the liberation of many people from the Nazi invaders. I hope that you know about this from your history lessons in school. And today we want very much to live in peace, to trade and cooperate with all our neighbors on this earth...with those far away and those near by. And certainly with such a great country as the United States of America.

In America and in our country there are nuclear weapons...terrible weapons that can kill millions of people in an instant. But we do not want them to be ever used. That's precisely why the Soviet Union solemnly declared throughout the entire world that never...never...will it use nuclear weapons first against any country. In general we propose to discontinue further production of them and to proceed to the abolition of all the stockpiles on Earth.

It seems to me that this is a sufficient answer to your second question: 'Why do you want to wage war against the whole world or at least the United States?' We want nothing of the kind. No one in our country— neither workers, peasants, writers nor doctors, neither grown-ups nor children, nor members of the government—want either a big or 'little' war.

We want peace...there is something that we are occupied with: growing wheat, building and inventing, writing books and flying into space. We want peace for ourselves and for all peoples of the planet. For our children and for you, Samantha.

I invite you, if your parents will let you, to come to our country, the best time being this summer. You will find out about our country, meet with your contemporaries, visit an international children's camp — 'Artek' — on the sea. And see for yourself: in the Soviet Union, everyone is for peace and friendship among peoples.

Thank you for your letter. I wish you all the best in your young life.

"Y. Andropov"

A media circus ensued, with Smith being interviewed by Ted Koppel and Johnny Carson, among others, and with nightly reports by the major American networks. On July 7, 1983, she flew to Moscow with her parents, and spent two weeks as Andropov's guest. During the trip she visited Moscow and Leningrad and spent time in Artek, the main Soviet pioneer camp, in the town of Gurzuf on the Crimean Peninsula. Smith wrote in her book that in Leningrad she and her parents were amazed by the friendliness of the people and by the presents many people made for them. Speaking at a Moscow press conference, she declared that the Russians were "just like us". In Artek, Smith chose to stay with the Soviet children rather than take the privileged accommodation offered to her. For ease of communication, teachers and children with fluent English were chosen to stay in the building where she was lodged. Smith shared a dormitory with nine other girls, and spent her time there swimming, talking and learning Russian songs and dances. While there, she made many friends, including Natasha Kashirina from Leningrad, a fluent English speaker.

Andropov, however, was unable to meet with her during her visit,although they did speak by telephone. It was later discovered that Andropov had become seriously ill and had withdrawn from the public eye during this time.Smith also received a phone call from Russian cosmonaut Valentina Tereshkova, the first woman to orbit the Earth. However, not realizing with whom she was speaking, Samantha mistakenly hung up after only a brief conversation. Media followed her every step...photographs and articles about her were published by the main Soviet newspapers and magazines throughout her trip and after it. Smith became widely known to Soviet citizens and was well regarded by many of them. In the United States, the event drew suspicion and some regarded it as an "American-style public relations stunt".

Smith's return to the U.S. on July 22, 1983, was celebrated by the people of Maine with roses, a red carpet, and a limousine and her popularity continued to grow in her native country. Some critics at the time remained skeptical, believing Smith was unwittingly serving as an instrument of Soviet propaganda. In December 1983, continuing in her role as "America's Youngest Ambassador", she was invited to Japan, where she met with the Prime Minister Yasuhiro Nakasone and attended the Children's International Symposium in Kobe. In her speech at the symposium, she suggested that Soviet and American leaders exchange granddaughters for two weeks every year, arguing that a president "wouldn't want to send a bomb to a country his granddaughter would be visiting". Her trip inspired other exchanges of child goodwill ambassadors, including a visit by the eleven-year-old Soviet child Katya Lycheva to the United States. Later, Smith wrote a book called Journey to the Soviet Union.

Smith pursued her role as a media celebrity when in 1984, she hosted a children's special for the Disney Channel entitled Samantha Smith Goes To Washington...Campaign '84. The show covered politics, where Smith interviewed several candidates for the 1984 presidential election, including George McGovern and Jesse Jackson. Her fame resulted in Smith becoming the subject of stalker Robert John Bardo, the man who would later go on to stalk and ultimately murder My Sister Sam actress Rebecca Schaeffer.

In 1985 she co-starred with Robert Wagner in a television series called Lime Street.

On August 25, 1985, Samantha and her father were returning home aboard Bar Harbor Airlines Flight 1808 after filming a segment for Lime Street. While attempting to land at Lewiston-Auburn Regional Airport in Auburn, Maine, the Beechcraft 99 commuter plane struck some trees short of the runway and crashed, killing all six passengers and two crew on board.Much speculation regarding the cause of the accident circulated afterwards. Accusations of foul play circulated widely in the Soviet Union. An investigation was undertaken in the United States and the official report...which did not show evidence of foul play...was made public. As stated in the report, the accident occurred at about 22:05 EDT, the ground impact point located one mile (1.6 km) south-west of the airport, at . The report goes on to say, "The relatively steep flight path angle and the attitude (the orientation of the aircraft relative to the horizon, direction of motion etc.) and speed of the airplane at ground impact precluded the occupants from surviving the accident." The main point of the report was that it was a rainy night, the pilots were inexperienced, and an accidental, but not uncommon and not usually critical, ground radar failure occurred.

Samantha Smith was mourned by about 1,000 people at her funeral in Augusta, Maine, and was eulogized in Moscow as a champion of peace. Attendees included Robert Wagner and Vladimir Kulagin of the Soviet Embassy in Washington, who read a personal message of condolence from Mikhail Gorbachev, while President Reagan sent his condolences to Smith's mother, in writing,

"Perhaps you can take some measure of comfort in the knowledge that millions of Americans, indeed millions of people, share the burdens of your grief. They also will cherish and remember Samantha, her smile, her idealism and unaffected sweetness of spirit."

The remains of Smith and her father were cremated. Their remains were buried side-by-side in Estabrook Cemetery, Aroostook County, Maine.

[[Image:USSR stamp S.Smith 1985 5k.jpg|thumb|right|150px|1985 USSR stamp with "Samant[h]a Smit[h]" in Cyrillic]]Smith's contributions have been honored with a number of tributes by Russians and by the people of her home state of Maine. A monument to her was built in Moscow; "Samantha Smith Alley" in the Artek Young Pioneer camp was named after her in 1986. The monument built to Smith was stolen by metal thieves in 2003 following the dissolution of the Soviet Union in 1991. In 2003, Voronezh retiree Valentin Vaulin built a monument to her without any support from the government. The Soviet Union issued a commemorative stamp with her likeness. In 1986, when Soviet astronomer Lyudmila Chernykh discovered asteroid 3147, she named it 3147 Samantha. The Danish composer Per Nørgård wrote his 1985 viola concerto "Remembering Child" in memory of Smith. A diamond found in Siberia, a mountain in the former Soviet Union, a cultivar of tulips and of dahlias, and an ocean vessel have been named in Smith's honor. In Maine, the first Monday in June of each year is officially designated as Samantha Smith Day by state law. There is a bronze statue of Smith near the Maine State Museum in Augusta, which portrays Smith releasing a dove with a bear cub resting at her feet. The bear cub represents both Maine and Russia. Elementary schools in Sammamish, Washington and in Jamaica, New York have been named after Samantha. In October 1985, Smith's mother founded the Samantha Smith Foundation, which fostered student exchanges between the United States and the Soviet Union until it became dormant in the mid-1990s.