When Dan first appears he is seen riding his bike to the park, where he is supposed to battle Shuji. He managed to defeat him with ease. Later he was challenged to a rematch, which he accepts. Drago tries to make him stop fighting with him. After the vision was over, Drago and Fear Ripper appeared in the field and Drago was able to defeat him, giving Dan the victory. Dan was surprised hearing Drago talking to Fear Ripper and he decides that he was imagining that he was talking.
In episode 2, Dan then tried to get Drago to talk but to no avail. After hearing from Runo Misaki that there is a man named Masquerade who was sending people's Bakugan to the Doom Dimension Dan decides to battle him. When he went to the meeting point, he found Shuji and Akira waiting for him for another rematch. Dan unwillingly accepted and defeated Shuji's Ventus Bakugan with ease. After the battle, he ran into Masquerade and battled him. After losing two of his Bakugan to Reaper, he sends out Drago and he was losing the battle until Dan tried to activate an ability card, which Drago was able to exceed and cause the battle to end in a draw. However, as Masquerade left, he revealed that he was holding back, making Dan realize that Masquerade was much stronger than he had anticipated, and that he could have lost Drago.
In episode 3, Dan started training for when he would encounter Masquerade again. Around this time Drago started accepting him as his partner, hoping that with Dan's help he can stop Naga. However during the battle against Rikimaru Drago was constantly trying to warn Dan to be careful and to come up with a strategy but Dan did not listen. So he just threw in a random Bakugan until Rikimaru threw in Siege, and using his ability that requires two more Aquos Bakugan was able to send all of Dan's Bakugn, as well as his own, to the Doom Dimension. Although he was able to win in the end by anticipating Rikimaru's moves, he was angry at Dan because of his reckless actions that cause four Bakugan to be sent to the Doom Dimension. Because of this Dan threw Drago into the river, saying they were done.
During Lars Lion's test for Runo, a younger, illusionary Dan was used to make Runo realize that she can't be so stubborn and rash. He was the first person that Runo met when she moved into his town. They played baseball, but when Dan left Runo never caught his name.
During his test with Apollonir, he brawls against a clown on the moon. He wins by using a Fusion Ability Card, D-Strike Extreme. Although Drago doesn't evolve like the others, he is told that he needs to defeat all of his friends in order for Drago to evolve. He defeats Julie and Hammer Gorem, although he hesitates because he doesn't want her to fall off Gorem. He then defeats Marucho, Preyas, and Angelo/Diablo Preyas. While he planned on defeating Shun next, Blade Tigrerra requested that her and Runo brawl first, which he accepted and won. Finally, he battled Shun. Drago evolved after Dan won.
After Drago finally evolved, Masquerade sent a battle request to Joe for the Infinity Core, only to have Dan come to battle in his place. Alpha Hydranoid and Drago, now an Ultimate Dragonoid, finally brawl. He wins and finds out that Masquerade was actually Alice.
When the Brawlers went to Vestroia, Dan caught the eye of the Bakugan hybrids Tricloid and Rabeeder, which started to freak him out. He was given a clay heart by Tricloid, which actually turned out to be a key to allow Dan and Drago access into the world of Pyrus and Darkus. When in the Pyrus-Darkus world, he and Drago fought the Pyrus-Darkus hybrids Druman and Centorrior. They were saved by Nova Lion, an elderly Pyrus Tigrerra. He then decides to take them to the center of the universe. They were stopped by the hybrids again and beat them, however Nova Lion died. Dan then wishes Nova Lion was back during another battle with the hybrids, but somehow, Alice overheard him, but didn't know who he was talking about Alice then decided to become Masquerade one more time to save them, which she does, and thanks to Masquerade's plan, the hybrid Bakugan are defeated.
Although constantly arguing with each other, Dan and Runo are in love but don't confess until the end of the series, where they are seen going on a movie date together. Also, during this date, both Dan and Runo seem to both have changed clothes.