Bruno Ganz, the Swiss actor who played Adolf Hitler in the film Downfall, has died in Zurich at the age of 77, his agent said on Saturday.

The actor became internationally renowned for his 2004 portrayal of the dictator of Germany in the final days inside his Berlin bunker.

In a Guardian review of the film Rob Mackie described Ganz as “the most convincing screen Hitler yet: an old, bent, sick dictator with the shaking hands of someone with Parkinson’s, alternating between rage and despair in his last days in the bunker”.

His lengthy rants in the film became a recurrent meme with subtitles laid over the footage to create parodies of everything from sporting events to current affairs.

It is widely believed to be the cinematic footage most often shared online, as well as the cause of one of the world’s most productive internet memes.

Speaking to the Guardian in 2005, Ganz said that during the months of painstaking research, that involved looking at historical records including a secretly-recorded tape of Hitler, before taking on the role he became convinced that Hitler was suffering from Parkinson’s disease towards the end of his life.

He said: “There is newsreel of him presenting medals to the Hitler Youth a few days before his death, and you can see his hand shaking, so I visited a hospital and observed Parkinson’s sufferers.”

The actor also revealed that in taking on the role it was “useful to be able to put my Swiss passport between my heart and Mr Hitler, so that he couldn’t touch me”.

The actor said he was “fascinated” that “he was not just supported by the German people; he was loved”.

He added: “The relationship between him and them was almost religious. There was also that Wagnerian undercurrent – the hero dressed in white, standing against a corrupt world. Look at the bunker - the way Goebbels’s wife is willing to kill her children because she can’t imagine life after national socialism. It is like a cult. So it helped me that I am Swiss, not German.”

But Ganz added that he had not gained real insight into Hitler’s motivation, saying: “I cannot claim to understand Hitler. Even the witnesses who had been in the bunker with him were not really able to describe the essence of the man.”

On the actor’s 75th birthday the German news outlet Deutsche Welle reported that Ganz’s decision to quit school and pursue his dream of acting baffled his parents.

In the early days of his career he worked as a bookseller and a paramedic before he broke into film with roles in The Marquise of O, which won a special prize at Cannes in 1976, and Peter Stein’s drama Sommergäste (Summer Guests).

He also played Jonathan Harker in Werner Herzog’s Nosferatu the Vampyre (1979) and an angel in Wim Wenders’ Wings of Desire (1987) and its sequel Faraway, So Close! (1993).

In 2008 he appeared in The Baader Meinhof Complex and in 2018 he was in Lars von Trier’s The House that Jack Built.

At the time of his death Ganz was the holder of the Iffland-Ring – a diamond-studded ring stamped with the image of German actor August Wilhelm Iffland. It is passed from actor to actor to mark the recipient as the “most significant and worthy” German-speaking actor of their era.

It is not known to whom he had chosen to pass the heirloom at the time of his death.

Last year it was reported Ganz was suffering from intestinal cancer. He is survived by his son, Daniel.