Kohl served as chancellor for 16 years -- from 1982 to 1998 -- and was Germany's longest-serving leader since 1945. He worked tirelessly for the reunification of West and East Germany, the countries separated in the ashes of World War II.
"We have lost the father of modern Germany," British Prime Minister Theresa May said in a statement. "And my deepest sympathies and condolences are with his family and with the German people at this sad time."
"Helmut's death hurts me deeply," European Commission Chairman Jean-Claude Juncker said in a Twitter post. "My mentor, my friend, the very essence of Europe, he will be greatly, greatly missed."
Former US President Bill Clinton -- who honored Kohl with the Presidential Medal of Freedom in 1999
-- mourned the loss of his friend, saying his "visionary leadership prepared Germany and all of Europe for the 21st century."
"He was called upon to answer some of the most monumental questions of his time, and in answering them correctly he made possible the reunification of a strong, prosperous Germany and the creation of the European Union," Clinton said in a statement.
Kohl was born in Ludwigshafen am Rhein, an industrial port city in what is now the state of Rhineland-Palatinate.
He began working in the CDU in 1947. He served in the Rhineland-Palatinate legislature from 1959 to 1976, and served as minister-president of the same state from 1969 to 1976.
Kohl was CDU chairman from 1973 to 1998. He was a member of the Bundestag, West German's lower house of Parliament from 1976 to 1990.
He became chancellor of West Germany in 1982 and served until 1990, then became chancellor of Germany after reunification.
His chancellorship was marked with centrist policies that stressed commitment to NATO and modest cuts in spending.
After the Soviet Union relinquished control of Eastern Europe, Kohl launched his push for reunification, with constant reassurances to Western leaders that a united Germany posed no threat.
Reunification was consummated with the dissolution of communist East Germany.
The fusion of East and West after decades of forced separation occurred after Kohl secured the approval of NATO and the Soviet Union.
"I will never forget walking with him through the Brandenburg Gate in 1994 for a large rally on the eastern side, and seeing genuine hope in the eyes of tens of thousands of young people. I knew at that moment that Helmut Kohl was the man who could help them realize their dreams. History continues to prove that he delivered," Clinton said.
Dissatisfaction with Kohl's rule and high unemployment led to his defeat in 1998 by the Social Democrats. Kohl was succeeded in the chancellorship by Gerhard Schroeder.
Honors and a scandal since '98
Along with his honor from Clinton, Kohl was named an Honorary Citizen of Europe for his work in the integration of Europe and was regarded as a great statesman.
But he faced a political scandal after his days in office.
In 1999, he admitted that he accepted anonymous political donations between 1993 and 1998, totaling more than $1 million. Under German law, acceptance of such funds is a crime.
The fund-raising spurred an investigation in 2000. Kohl, who refused to discuss details of the funds, was harshly criticized.
The criminal investigation into illegal fund-raising was dropped in 2001. Kohl agreed to pay a fine of 300,000 German marks ($142,000).