Jack Wilton exhibits a range of moods and goes through many colourful experiences in this story, but it cannot be said that he changes or develops significantly as a character. He does claim at the end to have been suitably chastened by the often horrific sights he has seen and the perils he has passed through, particularly the stomach-churning episode involving Cutwolfe and Esdras:
To such straight life did it thenceforward incite me that ere I went out of Bologna, I married my courtesan, performed many alms-deeds, and hasted so fast out of the Sodom of Italy that within forty days I arrived at the King of England’s camp twixt Ardres and Guines in France ...
Jack, then, finishes by declaring that he has been sobered into leading a better life, leaving the scene of the most lurid of his adventures, Italy, which often appears as a grim, bloodthirsty land in Elizabethan literature (note how Jack refers to it as 'Sodom', the ancient city legendary for its wickedness). However, this change holds little, if any psychological interest. His main function is to narrate his numerous adventures and entertain the reader in this way.
The lack of real development in Jack's character is significant as it helps illustrate what kind of work this is. As a fictional work of prose it is sometimes cited as a proto-novel, but unlike most novels it is more concerned with providing a series of sensational adventures than with character development. It might be called a picaresque narrative, like the Spanish work Don Quixote, as it features the various, and often improbable, escapades of its main character. However, although Jack is a lively narrator, he does not appear as a fully-rounded character in his own right.