Bruce is a kind and pleasant shark. He is also shown to be jolly, laid-back, and a jokester. He is also honest and well-meaning. However, his personality is completely different when his instincts start to kick in and change him into a mindless, fish-eating shark (temporarily).
Bruce is first seen in the film 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 with a huge grin, 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 were not 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 is like a party and Bruce goes along with it and asks if they are 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. Bruce soon comes to an old abandoned minefield where Dory mistakes the bombs for balloons, to which Bruce laughs and tells them that they would not 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. He calls the two sharks (who were complaining that Bruce was late and that they were hungry) that they have company. 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. 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. As 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.
Although Bruce does not appear in Finding Dory, he is indirectly mentioned along with Chum and Anchor by Marlin to Nemo during a dialogue.
In a character interview, which is available in the "Behind the scenes" menu on the first film's DVD, Marlin and Dory wonder where Nemo went, until realizing he went into Bruce's mouth. As Marlin orders Nemo to swim out, Bruce remarks that he had just cleaned his teeth. Then, as the interviewer urges a reluctant Marlin to tell the viewers how he and Dory saved Nemo, Bruce has enough and ends the interview by breaking the camera with his teeth.
An emoticon version of Bruce appeared in the Finding Nemo entry of the As Told by Emoji short series.
Bruce is seen in the Finding Nemo Submarine Voyage, where Nemo, Squirt, and the player swim away from getting eaten by Bruce while in his frenzy when he smelled Nemo's blood from touching a nail with his fin. In the end, he swallows a tire and it gets stuck in his throat as he tried to cough it up, but with the help of Nemo, he successfully gets it out and after recovering from his frenzy, apologizes to Nemo and Squirt.
Bruce makes a cameo in the Finding Dory Play Set, where in the first level, he briefly goes savage and almost bites the player's character.
He also makes a brief appearance in The Seas with Nemo & Friends, in the shipwreck section, where he tries to get Nemo to come out of hiding and "join him for a bite".
Bruce also appears in Finding Nemo Submarine Voyage, in the shipwreck section. There, he sees the people in the submarine, and clearly wants to eat them, so he says that he isn't going to eat them, or at least "not all at once", but then is reminded of the Fish-Friendly pledge by Chum. After reciting the pledge, and as the riders' submarine enters the minefield, Bruce warns them to try not to touch the "balloons", or else they'll "pop", but the submarine accidentally touches the mines, and Bruce and Chum swim away as the mines explode.
- Bruce is named after the villainous great white shark from the 1975 film, Jaws. In said film, the shark has no given name, but the shark models used in the film were all named "Bruce".
- Another reference to Jaws is shown in the scene when Dory and Marlin are stuck in one of the submarine's torpedo tubes and fire 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 through a door in the submarine. 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 axe 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 of which can be animated individually.
- Bruce never knew his father. In real life, great whites never care for their pups and leave them, as their pups are highly precocial.
- He also seems to have a closer friendship to Dory than Anchor and Chum.
- It is unknown what Bruce's opinion on dolphins is. While Anchor and Chum were making fun of dolphins, Bruce did not say anything; he just called the meeting to order.
- Ironically, great whites are one of the few sharks who are known to hunt and eat dolphins.
- The group that Bruce runs is very similar to Alcoholics Anonymous.
- Despite being a male shark, Bruce for some reason does not have any claspers. This is a trait he shares with his friend Anchor. This is likely for censorship purposes, as claspers are reproductive anatomical features specific to male sharks. Bruce's other friend, Chum, however, does have claspers.
- Great Whites in real life would not bother chasing fish like Marlin and Dory as they are too small and thin to provide the calories necessary to keep a giant shark going.
- Many sharks in real life are incapable of remaining still because water needs to continually pass over their gills for them to breathe. This process is known as ram ventilation. Bruce and his friends, however, are shown to stay perfectly still on multiple occasions. Sharks such as the bullhead and nurse species can remain still because they have other adaptations that allow them to run water over their gills without needing to move. This is possible due to buccal pumping (muscles near the mouth move water over their gills) and prominent spiracles that are located behind a shark's eyes and allow water to be moved even when these kinds of sharks are under the sand.
- Great white sharks, mako sharks, and hammerhead sharks are obligate ram ventilators, so they must all keep moving in order to breathe, making these instances of character pause zoological fallacies for all three sharks.