The church gained fame - and notoriety - in the 1970s and 1980s for holding mass weddings of thousands of followers, often from different countries, whom Mr. Moon matched up in a bid to build a multicultural religious world.
The church was accused of using devious recruitment tactics and duping followers out of money; parents of followers in the United States and elsewhere expressed worries that their children were brainwashed into joining. The church responded by saying that many other new religious movements faced similar accusations in their early stages.
In later years, the church adopted a lower profile and focused on building a business empire that included the Washington Times newspaper, the New Yorker Hotel in Manhattan, Bridgeport University in Connecticut, as well as a hotel and a fledgling automaker in North Korea. It acquired a ski resort, a professional soccer team, and other businesses in South Korea, and a seafood distribution firm that supplies sushi to Japanese restaurants across the U.S.
The Unification Church claims millions of members worldwide, though church defectors and other critics say the figure is no more than 100,000.
In 2009, Mr. Moon married 45,000 people in simultaneous ceremonies worldwide in his first large-scale mass wedding in years. Some were newlyweds and others reaffirmed their vows. He married an additional 7,000 couples in South Korea in February 2010. The ceremonies attracted media coverage but little of the controversy that dogged the church in earlier decades.
Born in 1920 in what is today North Korea, Mr. Moon said he was 16 when Jesus Christ called upon him to complete his unfinished work. While preaching the gospel in North Korea in the years after the country was divided into the communist-backed North and U.S.-allied South, Mr. Moon was imprisoned in the 1940s for allegedly spying for South Korea - a charge he disputed.
He quickly drew young followers with his conservative, family-oriented value system and unusual interpretation of the Bible. He conducted his first mass wedding in Seoul in the early 1960s.
The "blessing ceremonies" grew in scale over the next two decades, with a 1982 wedding at Madison Square Garden in New York - the first outside South Korea - drawing thousands of participants.
"International and intercultural marriages are the quickest way to bring about an ideal world of peace," Mr. Moon said in a 2009 autobiography. "People should marry across national and cultural boundaries with people from countries they consider to be their enemies so that the world of peace can come that much more quickly."
Mr. Moon began rebuilding his relationship with North Korea in 1991, when he met the country's founder, Kim Il Sung, in the eastern industrial city of Hamhung.
He said in his autobiography that he asked Kim to give up his nuclear ambitions, and that Kim responded that his atomic program was for peaceful purposes and he had no intention to use it to "kill my own people."
"The two of us were able to communicate well about our shared hobbies of hunting and fishing. At one point, we each felt we had so much to say to the other that we just started talking like old friends meeting after a long separation," Mr. Moon wrote.
He added that he heard Kim tell his son: "After I die, if there are things to discuss pertaining to North-South relations, you must always seek the advice of President Moon."
When Kim Il Sung died in 1994, Mr. Moon sent a condolence delegation to North Korea, drawing criticism from conservatives at home. Kim's son and successor, Kim Jong Il, sent roses, prized wild ginseng, Rolex watches, and other gifts to Mr. Moon on his birthday each year. Kim Jong Il died last year and was succeeded by his son Kim Jong Un. Mr. Moon sent a delegation to pay respects during the mourning period.
Mr. Moon also developed good relationships with conservative American leaders, including former Presidents Richard Nixon, Ronald Reagan, and George H.W. Bush. Still, he served 13 months at a U.S. federal prison in 1984-1985 for tax evasion. The church says the U.S. government persecuted Mr. Moon because of his growing influence and popularity with young people in the United States, his home for more than 30 years.
As he grew older, Mr. Moon quietly handed over day-to-day control of his multibillion-dollar religious and business empire, which included dozens of companies, including hospitals and universities and a ballet troupe, to his children.
His youngest son, the Rev. Hyung-jin Moon, was named the church's top religious director in April 2008. Other sons and daughters were put in charge of the church's business and charitable activities in South Korea and abroad.
After ending a first marriage, Mr. Moon married a South Korean, Hak Ja Han Moon, in 1960. She often was at his side for the mass weddings.
Mr. Moon is survived by his second wife and 10 children.