He is Prince John's right-hand man who enforced the prince's taxing. He is seen at the beginning of the film, ready to ambush Robin Hood with a trap with real gold on a wagon. However, due to Jerry, Robin's messenger, the rider of the wagon was captured five miles back and was replaced with Little John. When The Sheriff says it's still 10 to 2 (2 and 1/16 when Jerry got offended), the rest of Robin's Merry Men ambush the Sheriff and his guards, strip them to their underwear, and take the gold.
The Sheriff escapes and reports to Prince John. The Sheriff believes there's a spy in the castle and hires Tom, to catch Jerry which would reveal the spy. Maid Marian leaves the table to her room while she is oggled by the Sheriff (and three wolf guards) The Prince worries that once the Crusades were over, his brother, Richard the Lionheart would return. The Sheriff assures the Prince that Crusades were dangerous and Richard might never return.
When Tom is unable to catch Jerry, the Sheriff and John plan an archery contest with promises of gold, the title of best archer in the land, and a kiss from Maid Marian, hoping it would trap Robin. Robin (in a disguise) and the Sheriff become the last two to compete. The Sheriff makes a bullseye. Jerry, trying to escape Tom, puts himself in Robin's quiver and ends up on the arrow he planned to use. Tom attacks Robin's leg and he shoots his arrow in the air. Jerry manuevers the arrow and it goes through three bullseyes, making Robin win. The Sheriff removes Robin's disguise and he is arrested.
Jerry heads to the castle to save Robin and fights with Tom in Maid Marian's room who is writing Robin a letter. The two fall out a window when they fight near the door when the Sheriff enters her room because as the default winner, he wanted a kiss. He sees something behind Maid Marian and grabs the note learning she is the spy. He offers to spare her fate if she agreed to become his wife. She says she wouldn't marry him if he was the last man on earth and calls him "Sheriff of Nothingham," which is his pet peeve. She then says she would rather be finished off by the executioner's axe than be his wife. The Sheriff said that could be arranged and storms off. He calls the wolf guards to make sure if she tried to escape, they would finish her. The wolf guards were uncertain as "she was the only girl in the whole picture," but they stood guard.
Jerry gets stuck in a bottle as Tom and Jerry get into another window and Tom is able to trap him. When he goes to show the Sheriff, he pushed Tom away. The Prince's spies reveal that Richard would return tomorrow. The Sheriff offers to make sure the King never reaches shore and requests Maid Marian's execution, terrifying Tom. Once the Prince and Sheriff leave with some soldiers, Tom lets Jerry escape and then tears off the Prince's emblem from his shirt and teams up with Jerry to help Robin. Meanwhile Maid Marian is able to defeat the wolves by using their crush on her to make them turn on each other. Robin and Marian reunite and discover The Prince and John's plans and go to save him. Robin puts Jerry on an arrow and Jerry knocks Richard down preventing his death from the soldiers' arrows. The Prince and Sheriff get some of their soldiers to help them kill Robin and Richard who got to a broken ship. After subduing the guards, Robin and Richard get trapped under some ropes used for the sails and the Prince and Sheriff prepare to kill their enemies. Tom and Jerry knock the two down and fight them long enough for Robin and Richard to escape. Once Robin and Richard get free, both the Prince and Sheriff get trapped in a net, putting an end to their threat.
It's likely they both get sent to the dungeons for their crimes.