The youthful-looking 42 year old economist has not risen through the ranks of a political party to build his stellar career, instead spending time at the Bank of France and International Monetary Fund, where he worked on African issues.
Weidmann became Merkel's close adviser on economic affairs in 2006 and has been part of the influential Group of Eight nations "Sherpa," playing a key role in clinching global agreements.
The German daily Die Welt has called him: "He who whispers in the chancellor's ear."
Weidmann replaces outgoing Bundesbank president Axel Weber, who decided to step down at the end of April, casting doubt over who would become the next European Central Bank president, a role many thought Weber would take on.
Weidmann has also made a name for himself as secretary of the German Council of Economic Experts, the "Five Wise Men" who advise the government, and at the
Bundesbank, where he directed the monetary policy and analysis division.
He was sent to Berlin by Weber, one of Weidmann's economic professors in Bonn who was impressed by his student's grasp of economic theory and pragmatism.
Weidmann "combines a solid background in economics with first-hand experience in containing severe financial crises in Europe," Berenberg Bank chief economist Holger Schmieding told news agency AFP.
He worked feverishly behind the scenes to hammer out rescue plans for German banks embroiled in the global financial crisis and for carmaker Opel.
"No position is likely to be as exciting" after such experiences on the brink of disaster, the German daily Süddeutsche Zeitung commented in an article about Weidmann.
The newspaper also noted that one of his top priorities seemed to be to "go unnoticed."
Speculation as to his future grew in January when Weidmann was named to replace an outgoing member of the Bundesbank board which is based in Frankfurt, with his wife and two children close by.
Some suggest the choice could fuel speculation it was more political than practical.
Barclays Capital economist Thorsten Polleit told AFP that "eyebrows might be raised" at the path leading straight from Merkel's office to the central bank.
Schmieding noted however that "history shows that, (once) in office in Frankfurt, Bundesbankers are fully independent of those who had appointed them."