- "I am a nice shark, not a mindless eating machine. If I am to change this image, I must first change myself. Fish are friends, not food."
- —Brucey reciting the Fish-Friendly Sharks motto
Bruce is a kind and pleasant shark. He is also shown to be jolly, laid-back, and a jokester. However, his personality changes when his instincts start to kick in, and this makes him turn into a mindless, fish-eating shark (temporarily).
Bruce is first seen when Marlin accidentally comes face-to-face with him when the clownfish began to swim off to go find his son Nemo. Even after Bruce politely introduced himself, Marlin and Dory seemed uneasy. Seeing this, Bruce said that he understood, saying, "Why trust a shark, right?" He then turns to leave, only for the shark to turn quickly and snap his teeth at them, just barely missing their mark. Even though it scares Marlin (who hides behind Dory) and Dory, Bruce gets a good laugh out of it. After he calms down, he asks what a couple of "bites" like them were doing out. When Marlin says they weren't doing anything, Bruce takes advantage of this and asks if they would like to get to a little get-together that he was hosting. Dory asks if it's like a party and Bruce goes along with it and asks if they're up to going. Dory readily agrees, but Marlin is very hesitant, and before the clownfish could swim away, Bruce blocks his path and tells Marlin that he insists and begins to lead the two fish away. Soon, Bruce comes to an old abandoned minefield where Dory mistakes the bombs for balloons, to which Bruce laughs and tells them that they wouldn't want any of the bombs to pop. As Bruce continues to swim through the minefields, a submarine comes into view. Bruce then pushes Marlin and Dory to an opening where two sharks named Anchor and Chum (who appear to be Bruce's buddies) are swimming around in circles. The two sharks complain that Bruce was late and that they were hungry. As Bruce pushes Marlin and Dory closer, it is thought that Bruce has brought them so that his friends could eat them as Anchor opened his mouth to swallow the scared Marlin.
However, in the next scene, Bruce rings a bell and says that a meeting has come to order and they then say their pledge: "I am a nice shark, not a mindless eating machine. If I am to change this image, I must first change myself. Fish are friends, not food." After the pledge (and after Anchor and Chum start to complain about dolphins), Bruce announces that the meeting was "Step Five: Bring a fish friend." When he asks if they all have a friend, he's pleased to see that Anchor had one (who appeared to be a little fish named Blenny). He then asked where Chum's friend was; when told that his friend was misplaced, Bruce offered Chum one of his own friends (Marlin and Dory). The Great White then says that he had not eaten a fish in 3 weeks, which amazes Anchor and Chum. Bruce then invites Dory (who is excited) to go next. After Dory says that she had never eaten a fish, Bruce and his friends applaud her (and Chum accidentally keeps hitting Marlin with his fin while clapping). After asking who was to go next, Bruce looks at Marlin, asking what his "problem" was. Bruce then pushed Marlin onto the "stage" when the annoyed clownfish said that he didn't have a problem. As Marlin introduced himself as a clownfish, Anchor and Chum got very excited, which ended up with Bruce pushing Chum out of the way so to get close to Marlin and urged him to tell a joke. However, as Marlin starts to rant during his joke, Bruce starts to lose interest. He then murmurs to Anchor that even as a clownfish, Marlin wasn't that funny. When Marlin swims to a scuba diver's mask, he tells the sharks that Nemo was taken from him. Bruce is touched when he finds out that Marlin was looking for Nemo. The shark then breaks down into tears and confesses that he never knew his father, which in turn got him a couple of hugs from Anchor and Chum, who tried to cheer their mate up.
Meanwhile, Marlin and Dory find the scuba diver's mask and as Dory is about to ask the sharks to read what it says, Marlin pulls on the mask and Dory pulls back. This makes Marlin let go by accident and the mask hits Dory on the face, causing some blood to spill into the water. Bruce, having just watched all of this, begins to ask Dory if she's okay, but is cut off when he smells her blood. Bruce's natural instincts kick in, his eyes go from a bright blue to a pitch black color, and just as he is about to eat his two fish friends, he is pinned to the wall by Anchor and Chum (who quickly decided to intervene and save Marlin and Dory). Finally, Bruce gets free from Anchor and Chum and charges after Marlin and Dory, shouting that he's having fish tonight. He then goes on a hunt after Marlin and Dory, having a few close calls until Marlin and Dory swim into a room and the door closes, making Bruce slam into the door painfully. As the terrified fish look for an escape, Bruce begins to ram against the door, loosening the bolts. Just as Dory and Marlin escape the submarine, Bruce crashes through an escape latch and continues to chase after the fish, finally cornering them in a torpedo tube. In his frenzy, Bruce begins to ram the opening in a futile attempt to get to the trapped fish, nearly crushing Anchor and Chum as they apologized. While stuck inside, Marlin tells Dory that they have to get the mask from Bruce, which had gotten caught in his teeth during the chase. Dory then finds a way to release the torpedo and sends it into Bruce's mouth, momentarily lodging it into his throat, during which Dory and Marlin grab the mask and retreat into the tube. Angered, Bruce swings his head and successfully gets the torpedo out of his mouth, not noticing that he has sent it flying towards one of the active mines. Chum calls out to Bruce, who then takes notice. Now back to his old self while fearing for their lives, he yells for his fish friends to swim away.
After this, the sharks' fates are unknown until the end, where it is revealed that they have survived the explosions. At the end of the movie, Bruce and his friends are shown at the reef, dropping off Dory after one of their meetings before swimming away.
On the DVD Easter egg, there's also a scene of Bruce and Dory. In it, Dory is seen playing with Bruce, in which she tickles his belly, making him laugh. The scene ends with Dory swimming off-screen, with Bruce following her.
Bruce appears in the Finding Nemo computer games. In one game, he plays a game with Nemo and asks him to shoot seaweed balls into his mouth. In another game, he appears in his meeting and when clicked on, he'll talk.
- Bruce is named after the villainous great white shark from Jaws. In said film, the shark has no given name, but the shark models used in the film were all named "Bruce" after director Steven Spielberg's lawyer, Bruce Raymer, hence Bruce's name.
- "Bruce" is also the stereotypical name for any male Australian, just as "Mick" or "Paddy" is for an Irishman and "John Bull" is (though now rarely) for an Englishman.
- Another reference to the Steven Spielberg film Jaws is shown in the scene when Dory and Marlin are stuck in a torpedo tube, and they release the torpedo, which gets stuck in Bruce's mouth, allowing them to escape.
- At one point during the chase scene, Bruce manages to partially break a door in the submarine open. He then sticks his head into the opening and shouts, "HERE'S BRUCEY!" This is obviously a reference to a famous scene in Stanley Kubrick's 1980 horror film The Shining, when Jack Nicholson's character uses an ax to smash part of the door to the room where his wife is hiding, then sticks his head into the opening and shouts, "HERE'S JOHNNY!"
- Bruce has 202 teeth in his mouth, each one of which is individually animatable.
- Bruce never knew his father, so he was likely closer to his mother. Ironically, real great whites never care for their babies and leave them, as their babies are highly precocial.
- He also seems to have a closer friendship to Dory than Anchor and Chum.
- It's unknown what Bruce's opinion on dolphins is. He may be the kind that doesn't mind dolphins, as long as they don't bother him. While Anchor and Chum were making fun of dolphins, Bruce didn't say anything; he just called the meeting to order (as shown in the movie).
- The group that Bruce runs is very similar to Alcoholics Anonymous.
- Despite being a male shark, Bruce for some reason doesn't have any claspers. Anchor also lacks claspers, but Chum does possess claspers.