Little John, a brown bear, is Robin Hood's best friend and most loyal partner.  Like Robin, he wears a dark green tunic and a feathered cap.  As fellow rogues, John and Robin behave as honorable thieves, their goal being to "rob the rich to feed the poor".  Both of them feel obligated to taking care of and looking after the common peasants of Nottingham, and also of resisting the corruption of Prince John and his cronies (including the Sheriff of Nottingham) until the return of King Richard from the Crusades. 

Like Robin, Little John is a master of disguise and role-play.  He's also a good fighter and brawler, and would gladly lay down his life for his friend.  John also tends to be a voice of reason whenever Robin is feeling mischievous (or at least he attempts to be), and likes to look after Robin and attend to many of the very mundane chores of living and hiding in the depths of Sherwood Forest.

Little John speaks with a general American accent and, rather like Baloo the Bear in Disney's The Jungle Book, in the manner of a 1950s beatnik.  His occasional use of beatnik slang is apparent (though Baloo used a great deal more, and acted more like a beatnik than Little John...which probably reflects the six-year gap between the production of the two movies).

Little John is also the only member of Robin Hood's band.  So, in effect, there is no real band of "Merry Men" in this movie (though Allan-a-Dale and even Friar Tuck, to varying degrees, appear in other versions of the Robin Hood legend as members of the band).

Origins of the character: Little John is arguably the most famous of Robin Hood's various "merry men".  According to The Robin Hood Project, by the Robbins Library of the University of Rochester (New York):

"Critical and literary attention has rarely deflected from Robin Hood to land upon Little John, despite the character's prominence in the early modern / late medieval tradition. There is a curious split within the early materials of the Robin Hood tradition: three of the four Scottish chronicles which include Robin Hood mention John as well, and John appears prominently in the four earliest surviving ballads, the texts which are the foundation of the literary Robin Hood; however, references to Little John are far rarer in the popular proverb tradition, as well as in the brief chronicle references to the tradition from within a larger cultural context. The division continues today—where modern audiences find Robin Hood, Little John is never be far behind, yet he remains a member of the supporting cast, and is seldom found in the spotlight himself."