Bert is a minor character in the first 3 seasons of Cobra Kai.
He joined the Cobra Kai Dojo as it's youngest student so far. However, after being exiled by sensei John Kreese, for refusing to sacrifice a hamster, he joins Eagle Fang Karate and later on trains alongside Miyagi Do Karate after the dojos merge.
Bert along with several teenagers join the Cobra Kai Dojo after Cobra Kai student Miguel Diaz beats up Kyler and his gang in their school cafeteria. On his first day Bert along with the rest of the new students are roasted by the sensei Johnny Lawrence. While Johnny's insult causes several students to quit, Bert is not among the students that quit.
On the morning of the All Valley Karate Tournament Bert tells Cobra Kai students Aisha and Hawk that he does not think Johnny will come because the previous night he saw Johnny peeing on his car and ranting, and Johnny himself ranted to him. Johnny however shows up. Bert loses to his opponent in the tournament in the match before the quarter-finals. However, all the other Cobras, to include Johnny, think it was lopsided, as Bert was paired against a much bigger kid. After Miguel wins the tournament Bert along with the other students celebrate with him.
Bert has a much smaller role. He is still a student at the Cobra Kai. When Johnny punishes Aisha and the others for goofing off by teaching them about concrete, Bert is seen mixing the concrete with the others (but not one of the boys made to push the cement drum). In Episode 9 he is seen welcoming Raymond, also known as Stingray. When the School brawl occurs Bert fights Miyagi-Do Karate student Nathaniel. Nathaniel has more hits but mid-fight Bert manages to break his glasses, but this causes Nathaniel to tackle him to the ground and repeatedly punch him. However, a security guard arrive and picks up Nathaniel. Bert then tries to attack him but the security guard grabs his hand and takes them away to the principal's office.
While Bert isn't present when Johnny's sensei John Kreese takes over that could be attributed to him being in the principal's office because of his fight with Nathaniel. Since he was more than willing to attack a Miyagi-Do student it can be implied that Bert has been corrupted by Kreese's ruthless teachings, or it may have been motivated by his rivalry and disdain for Nathaniel.
After two weeks later, Bert returns to school because he was suspended because of the fight with Nathaniel. He encounters Hawk and Mitch proceeds to walk, but they are confronted by their rivals Demetri, Chris, and Nathaniel. After verbal comment, Counsellor Blatt shows up if everything is ok and asks them to walk away.
In Cobra Kai Dojo, Kreese brings the mouse and asks his student Bert what he should name the mouse, he gives his name "Clarence". Kreese then shows a snake to the class and orders Bert to feed it. Kreese says that Clarence is going to be the snake's next meal. When Bert refuses to give the mouse up, Kreese does so and orders Bert out of his dojo, along with all other students who winced at seeing such a sight. He later joins Johnny's Eagle Fang Karate Dojo. On one night, Bert and the other Eagle Fang's students are invited to Samantha LaRusso's house, where Sam says they should work together. Initially, Bert along with the others sans Miguel and Sam are against this, but end up agreeing after Demetri makes a speech about needing to work together in order to stand up to Cobra Kai.
Bert is kicked through the window at the LaRusso house, showing his love for animals as he is tricked into thinking it was the LaRusso's cat, which in reality was a trap set by Cobra Kai ordered by Kreese. Bert and the others are then attacked by several of the Cobra Kai's. Despite struggling for a while, Bert and his friends prevail, partly due to Hawk turning on the Cobra Kai's. The following morning, Bert, the other Eagle Fang's and Hawk show up at Miyagi Do and all of them start learning with the Miyagi Do students under the leadership of Johnny and Daniel. Having befriended each other, Nathaniel and Bert shake hands before standing together as the training begins.
- Bert is the first Cobra Kai student who got kicked out of team.
- His actor Owen Morgan is a real life Karate Black Belt.
- His actor is best friends with Nathaniel's actor Nathaniel Oh in real life and they knew each other before the show, which is ironic, since their characters hate each other in the show.
- Bert shows his soft side when Kreese shows him a little mouse and when also he hears a meow in the LaRusso's house, which he thinks is a cat. This shows that he has a strong heart for animals. He also correctly answers Johnny's question that a mongoose can kill a cobra, although Johnny believes such animals are imaginary.
- Hawk stuck up for Bert when he was kicked out from Cobra Kai, showing the two were friends, even though Hawk eventually made up his mind and saw Bert as an outcast.