Jimmy is a youthful sailor aboard the SS Venture.
He's the lookout of the Venture and a close friend with first mate Ben Hayes who he sees as a father figure. He is much younger and something of a kleptomaniac, introduced stealing Jack Driscoll's pen when he gets him his lunch. After making Jimmy return the pen and chasing him off, Hayes tells Driscoll that Jimmy doesn't mean any harm, and tells him that he found him hiding in a cage some years ago, with his arm broken in two places, and "wilder than half the animals in here." Hayes says, further, "He still won't tell me where he came from, but it wasn't any place good."
In the scene where Kong attempts to bring back Ann Darrow, Jimmy shoots at Kong with a Tommy gun but is wounded when Kong throws his boat against a boulder. He is seen conscious but being held above water by Jack Driscoll, who was also in the same boat thrown against the boulder. He emerges in the video game, but he is not able to use guns, in spite of using them in the movie, and is show using a pistol in a scene before becoming an ally.