The Switzerland international, who is set to represent his country at the upcoming FIFA World Cup, won six Swiss Super League titles with Basel..
He is now relishing the challenge that awaits him in the German capital.
"I am excited about my move to the Bundesliga," Stocker told Hertha's official website.
"It was, from the beginning, my desire to go to Hertha Berlin. (General manager) Michael Preetz and coach Jos Luhukay worked very hard and for a very long time to get me.
"The task for Hertha is very exciting. Therefore I want to do my part to help the club enjoy success in the coming Bundesliga season."
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