The fall of the Berlin Wall gave Kohl a second chance to stay in office by positioning himself as a strong and reliable leader, and he seized the opportunity.
Kohl served for 16 years, from 1982-1998, and oversaw the end of the Cold War.
"This is the man who wants my job but he will not get it", is how Schmidt introduced Kohl to visiting U.S. President Gerald R. Ford.
Kohl died Friday at 87.
Leading in Germany's post-war reunification as the Cold War ended, Kohl was one of the leaders that played the framework for the European Union as we know it today was meant to be Germany's reunification architect, the chancellor that reshaped modern Europe.
Politicians from Germany and overseas paid tribute to the merits of the CDU politician about German unity and the convergence of Europe.
1984: Pays joint homage with French President Francois Mitterrand to the dead of World War I at Verdun, France.
He is also hailed for his contribution to Europe integration, European single currency and market.
"Believe me, Helmut Kohl will never become chancellor", proclaimed his arch-rival among conservatives, Bavarian Premier Franz Josef Strauss, after Kohl lost the 1976 election, "At the age of 90, he'll write his memoirs, Forty Years as a Chancellor Candidate".
European Commission President Jean-Claude Juncker tweeted: "Helmut's death hurts me deeply. In Russia, he will be remembered as a principled advocate of friendly relations between our countries", Putin said.
In western Germany, reunification soon also turned into a huge financial burden as it began to finance the formerly communist east.
Mentor to Merkel, Kohl was later ousted by his protege, who urged their party to drop the self-declared "old warhorse" when he became embroiled in a campaign finance scandal in 1999.
When Yeltsin passed away in 2007, Kohl called his death a heavy loss, saying that he remembered "with pleasure our honest and politically priceless meetings, during which he proved himself to be a reliable partner and a true friend".
Elation over German reunification ebbed amid the harsh realities of its cost and the difficulties of integrating east and west, but Kohl's coalition squeaked by again in 1994.
He says "among the State of Israel's greatest friends, he was completely dedicated to its security".
"We have lost the father of modern Germany and my deepest sympathies and condolences are with his family and with the German people at this sad time".
In a memoir, he quoted Thatcher as saying just after the Berlin Wall fell in 1989: "Twice we defeated the Germans! May Almighty God bless Helmut Kohl and the freedom he helped to secure", concluded Bush's statement.
For most of the 1990s, Kohl led the newly reunited nation, including becoming the heart of the European Union.
"Working closely with my very good friend to help achieve a peaceful end to the Cold War and the unification of Germany within North Atlantic Treaty Organisation will remain one of the great joys of my life", Bush said in a statement Friday.
Often harsh and thin-skinned, Kohl also could display a quick wit and jovial earthiness.
Ms Merkel grew up in communist East Germany.
"Helmut Kohl decisively influenced the course of my life, too", she said in Italy.
Federal Chancellor Angela Merkel (CDU) called her predecessor "a stroke of luck for us Germans".
Kohl's Christian Democratic Union party announced the news with a memorial message, reports CNN.
Bild newspaper said he died at home.