LeBoeuf is in either his late twenties or early thirties. He has auburn hair and a somewhat persistent cowlick. He fought for the Confederacy in the Civil War, serving with General Kirby Smith in Shreveport, 1863, and later with the Army of Northern Virginia. A proud Texan and Ranger, he is known to wield a Sharps Carbine of which he is very proud of, claiming that it is a precision machine in his hands.
During the events of True Grit, LeBoeuf is introduced to Mattie Ross before she sets out to find Chaney. Initially they butt heads, with Mattie insulting him several times. It is revealed that he has been tracking Chaney for some time, after Chaney killed a senator in Texas. He is denied the partnership but he soon comes to an agreement with Reuben Cogburn. The partnership is broken when the two have a small argument due to LeBoeuf's criticism of Rooster's war record.
He continues to pursue Chaney alone and runs into the Ned Pepper gang. The gang seizes him and drags him along behind a galloping horse. Rooster saves him, but in the process of saving him, Rooster accidentally shoots LeBoeuf in his shoulder. LaBoeuf nearly severs his tongue in consequence of being dragged behind a horse. LeBoeuf rejoins the two in tracking Tom Chaney. However, after having engaged in a significant number of arguments with Rooster, as well has differences in their methodologies (i.e. Rooster's drunkenness), it is obvious the two cannot work together and part ways.
LeBoeuf reappears the next day. He saves both Mattie and Cogburn, and kills Lucky Ned in the process.