Gunther graduated with a PhD in economics and statistics from the Friedrich-Alexander University Erlangen-Nurnberg (summa cum laude) and, between 1978 and 1994, was an economist in the German civil service and subsequently senior economist for the International Monetary Fund in Washington D.C.

After working for Salomon Brothers in London as managing director, in the late 1990s he founded a consultancy specialising in the analysis of central banks. In 2007 Gunther was appointed partner, CEO and chairman of the board of Brevan Howard Capital Management in Jersey, and, over the ten years there, built the offshore business and established the Jersey business as the hub of the Brevan Howard Group.