Joe looks to Tai as someone who is comfortable in his role in the group, which contrasted how he sometimes felt the opposite and thought he didn't have anywhere special in the group. But as the series continues, Joe slowly learns he is a valued member because of his maturity and his choice of being responsible for all, something Tai grows to respect. Tai relies on Joe for taking care of the others when he can't do this (Like when Joe stayed with Mimi during Puppetmon's saga), and sees him as a second leader in some moments. Their friendship is most seen in the episode "Princess Karaoke", when they're working together to get Mimi to come with them to rebuild the group.
After working side by side at a restaurant Matt and Joe became great friends with a great mutual respect for each other. Joe looks up to Matt greatly for his help and at one point went after him in Digimon Adventures, searching for his own path as well as Matt.
Joe teaches Sora the art of "mind over matter".
Although never explicitly stated, it is hinted at that Joe feels comfortable around Izzy since both kids are generally standoffish in that they each have their own social idiosyncrasies. In Adventure 02, the two seem to become kind of best friends, like in the Christmas episode, when Joe and Izzy sit together in Matt's concert, and after Joe held up Izzy's laptop, or when Joe needed help to get Whamon when the younger DigiDestineds were stuck in off shore oil platform, and contacted Izzy. In addition, The two help Cody Hida grow as a DigiDestined because of the fact he has the traits of knowledge like Izzy and reliability like Joe.
According to the Digimon Adventure novels, Joe was Mimi's camp counselor prior to the series' start.
As a result, Joe takes extra responsibility for Mimi and is aware that she is relies on him fo. He expresses frustration over her antics but accepts these and his job is to take care of her, as shown by how he follows her when Mimi leaves the group.
|This information is only considered valid within the English continuity.|
During the Tachikawa's vacation in Hawaii, Joe left Mimi a heart shape present suggesting he has a romantic feeling fo her.
Despite have being voted "The Most Likely to Chicken Out", in his school, Joe has risked his own life to save T.K. on at least two occasions. He is also one of the first to understand that T.K. is able to take care of himself, and doesn't always need to rely on others.
Joe, along with Tai and the others, takes some responsibility for Kari and feels that she and T.K. are important to the group. He helps her understand that everyone finds his/her role and that she would too.
When Davis and Joe interact, Joe passes on some wisdom to Davis which he seems to take to heart.
Joe sees Yolei as an important member of the new DigiDestined. She also was shown to appreciate his donating a hand-warmer to her in "Old Reliable."
Cody and Joe share the trait of reliability. He teaches Cody about the differences between a malicious lie and a good-intentioned lie. The younger boy is shown to look up to the older boy when they are in together.
While at first weary of Ken due to his formerly being the Digimon Emperor, Joe eventually comes to trust him and value him as a DigiDestined.