But Walter's daydreams are not helping him attract the attentions of work colleague Cheryl Melhoff (Kristen Wiig) or satisfy the demands of new boss Ted Hendricks (Adam Scott).
Walter is forced out of his comfort zone when a missing negative threatens to cost him and his offsider their jobs.
He must find the legendary and mysterious photographer Sean O'Connell (Sean Penn) wherever he is in the world and find that missing picture.
Spurred on by Cheryl, Walter goes on the adventure of his lifetime to Greenland, Iceland, Afghanistan and the Himalayas before he at last finds his man.
It is Walter's journey of discovery.
With nothing to lose and everything to gain, Walter charms his way across the globe with a big smile and friendly demeanour.
We are treated to some truly spectacular scenery in scenes clearly not shot in any Hollywood studio.
It is quite heartwarming watching Walter grow as his adventure progresses.
Although a touch disjointed at times with moments when you are not sure whether you are watching dreams or reality, The Secret Life of Walter Mitty is nevertheless an engrossing voyage through a simple man's wonderful life.
The Secret Life of Walter Mitty
(PG), 120 minutes