His haphazard off-the-cuff humour is nowhere to be seen as he brings to screen the finals days in the life of Henry Altmann.
Since his son died tragically two years earlier, Henry has had little joy in his life.
He is full of anger and everyone around him is fully aware of that.
Suffering with headaches, he goes to see his doctor only to find a young intern - Dr Sharon Gill (Mila Kunis) - standing in front of him.
When he launches into her, she tells him scans show he has an aneurism in his brain and has only 90 minutes to live.
And so starts a series of frantic dashes across town as he seeks to right the many wrongs he has committed in recent years. He has a brother, wife, son and friends to make amends with before it is time to meet his maker.
Chasing him across town is Dr Gill, who needs to get him to a hospital for treatment as soon as possible.
These 90 minutes allow Henry to see more clearly than he has in years and to understand the hurt he has caused to those around him, particularly his son.
The Angriest Man in Brooklyn shows the serious side of Robin Williams and was one of his final roles before his tragic deaths this year.
