Elstner went to school in Rastatt in Germany and gained his first experience in broadcasting as a child when he acted in radio plays for the station then known as Südwestfunk, now as Südwestrundfunk, which served the Rhineland Palatinate and southern Baden-Württemberg.

Today, Elstner mainly works for Südwestrundfunk (SWR) again (formed from the old Südwestfunk and Süddeutscher Rundfunk), presenting the talk show Menschen der Woche.

Since September 2002, he has worked for ARD as the presenter of the Saturday evening show Verstehen Sie Spaß?, the German equivalent of Candid Camera.

In 2006 Elstner was listed in the Rose d'Or Hall of Fame, on the 25th anniversary of his greatest success, Wetten, dass..?.

Since 12 September 2006, Elstner has presented the quiz show Die Besten im Südwesten ("The Best in the Southwest") on SWR.