On screen he has battled Nazis, stormtroopers and terrorists to save democracy, freedom or civilisation from clear and present danger.
Now Harrison Ford describes his latest role as a real-life fight for the future of this planet.
"What is at stake is the ability of nature to provide services to the human community that we can't afford to do for ourselves," said the actor, 68, in an interview with AFP.
He was speaking in the central Japanese city of Nagoya, where he is urging the 193 member countries of the UN's Convention on Biological Diversity (CBD) to use their 10-day meeting to protect vast swathes of the Earth's surface.
"Intact ecosystems provide us with fresh water, clean air, help produce healthy soils, are the source of genetic material from which to derive pharmaceuticals and regenerate our food supply.
"These are all the free services of nature," he said, but they are under threat from environmental degradation and "bold and decisive" action had to be taken now.
"One of our missions is to create a sense of urgency, help people understand that... just because they don't see it in their own lives, the effects are everywhere.
"Where it registers in everyone's life is in the economic impact; higher costs of food, depletion of fish stocks etc.
"The urgency can't be overemphasised... We are at a tipping point."
The Indiana Jones star - who had his chest waxed two years ago in a stunt to publicise tropical deforestation - insisted he had "really no ambition to be a celebrity spokesman for anything".
But he has sat on the board of the campaign group Conservation International for 20 years.
According to the organisation, 25 percent of the world's land surface needs to be protected and 15 percent of its oceans to effectively preserve biodiversity and combat global warming, up from the current 13 percent and less than one percent respectively.
"That's why our fishery is in such a poor shape - 70 to 80 percent of the fish that we eat are in danger of disappearing or close to extinction," said Ford.
The figures are the subject of tough negotiations in Nagoya, with no agreement reached by Wednesday.
A proposed compromise of 20 percent for land and 10 percent for seas was rejected earlier this week by several countries including China and India.
A global agreement was essential, said Ford.
"We all make small efforts in our lives and individual efforts do count but we have to really effect a change of scale that really is only possible through international engagements."
The American hoped that public opinion would ensure his country, one of the few not to have ratified the CBD, soon did so, saying it had so far not been politically "necessary".
"There are many many small victories, positive effects. Certainly we have encouraged the business community to behave more responsibly, we have educated them to the fact that consumer base now holds them responsible for their behaviour.
"The bigger picture is that we need to do more."
But he dismisses the idea that his own particular field, blockbuster cinema, can play a role.
While Al Gore's documentary An Inconvenient Truth "works very well", he said, "movies are there for the entertainment.
"Certainly we can engage people emotionally, but the solutions to the environmental issues are so much more complicated.
"We want people to recognise that solutions are complicated and specific. I am just not sure that the profit making movie business is the right place to deal with these issues."Reuse content