When Charlie's lack of money causes him to be thrown out of the cabaret, he returns to his open-air sleeping spot, unaware that crooks have buried a wallet there.  Scraps digs it up, covering Charlie's face with dirt in the process.  Charlie finds money in the wallet and takes it to the cabaret to show the girl that there is enough for them to get married on.  The crooks who buried the wallet spot Charlie and take back the stolen booty with some violence.  Charlie battles to get it back.  This leads to a chase which ends with the arrest of the crooks.  Charlie and the girl marry and use the money to buy a farm.  There they are seen looking fondly into a cradle which contains Scraps and her puppies.

Working under a million-dollar contract, this was Chaplin's first film for First National, a company which later merged with Warner Brothers.  Most of Chaplin's Mutual Company actors continued in his new films, but some new additions were made to the troupe, including his brother, Sydney.

What was said about A Dog's Life:

Los Angeles Examiner (Florence Lawrence)
Of course Chaplin uses his same funny hat and mustache.  These, like the wide trousers and strategic shoes, are part of his personality so far as the public is concerned, and a Chaplin comedy without them would be like Hamlet with the mad prince emitted from the cast.  But the star no longer depends upon his grotesque attire for his laugh. He shows us in this film some of the marvelous pantomime work for which his stage repute was high before films claimed him. In the scene of the stolen money he performs with his hands, which prove quite as capable at evoking laughs as ever his feet have been.

Chicago News (W. K. Hollander)
While Chaplin was in action loud guffaws of laughter greeted his comic capers.  They laughed at his vulgarities―Chaplin does not deport himself entirely above reproach―and applauded his nimbleness. He is admirably assisted by a remarkable canine which imitated its master's morbid and drowsy facial expression so well that one concludes it is a sort of Chaplin of the dog family.  This considerably adds to the fun.  This dog furnishes the reason for the specialty and inspires an exhilarating dog chase wherein Chaplin with the canine in his arms assumes the undignified role of the pursued with a motley pack of hounds behind him.

It is a strenuous chase, particularly for the comedian, for often the dogs meet up with him and bury their teeth into the tail end of his coat, hanging on until part of it gives away.  But Charles―not Charlie now―emerges triumphantly with the dog in his arms.  Chaplin puts a new dress on some old tricks and renders several comic novelties as well.  Above all, Chaplin is without―yes, it's true―his familiar cane.  He accomplishes his various stunts unassisted by his adjunct of previous activities.  In lieu of the stick he leads his pup about by a rope.