Gruff on the outside, but sweet on the inside, this bachelor field hamster likes being in charge. His name, Boss, may reflect what he wants to be, but he'd give his own helmet and shovel to a Ham-Ham in need. He has a bit of a temper, but he is very dependable, courageous, and even shy at times (especially around Bijou). His favorite phrase in the Japanese version is "Daji~e!" or "Dabba-to!".
Because he is a field hamster, he is more familiar with nature and is more independent compared to the other Ham-Hams. He has even developed a field hamster sense that instinctively tells him what kind of weather is approaching. However, he cannot deal with the sea as he is prone to seasickness. He lives alone in his house, which quickly becomes the Ham-Ham Clubhouse. Near the end of Hamtaro: Ham-Ham Heartbreak, it is hinted that he has a small crush on Harmony. Boss really likes Bijou, but Bijou likes Hamtaro. Boss later in the series has shown affection for other girl-hams such as Gelato and Oshare.
Starting from I'm Parting, Clubhouse!, Boss is absent from all the following episodes. The Ham-Ham Clubhouse is concealed until Boss's return, and the remaining Ham-Hams go on to discover Sweet Paradise and meet Lapis and Lazuli, marking the new season. In It's Your Turn, Hero-Ham!, he takes on a Hero-Ham persona in which he assists the Ham-Hams and others, who aren't aware it is really Boss. This act lasts until Here I Am, Clubhouse! when Hamtaro realizes Hero-Ham is really Boss. Afterward, Boss returns to the abandoned clubhouse. He occasionally returns to his Hero-Ham outfit in the future to help others and is typically in this form around Otome's Crew, who still are unaware who Hero-Ham really is.
After Hamtaro met Oxnard, they both fell into a tunnel, after which they met Boss. Hamtaro looks up to Boss, as he is older and usually wiser than Hamtaro, and they are very good friends. Boss is jealous that Bijou likes Hamtaro, but Hamtaro doesn't really notice. Perhaps Boss didn't value Hamtaro's friendship as much as he should until later, as shown in I'm Parting, Clubhouse! where he considers Hamtaro hypothetically leaving to just be another chance with Bijou.
When the Ham-Ham Clubhouse is finished being built in The Ham-Ham Clubhouse, Snoozer seemingly manifests into real life without explanation. Boss returns to the clubhouse to find him there, sleeping in a blue and yellow striped sock. Since then, Snoozer rests in the clubhouse, only leaving on a couple instances and "magically" appearing in the Sweet Paradise the same way he appeared originally in the clubhouse. This happens between episodes, I'm Parting, Clubhouse! and Lapis and Lazuli, because Boss is absent for a while and the clubhouse is locked up. After #194, Snoozer sleeps in Sweet Paradise instead until Boss returns later on. He is Boss' only company while the Ham-Hams are not around, so Boss holds him dear.
If Cappy looks up to Boss, Boss looks up to Sabu. In Boss Runs Away, Boss was overheard whining about his problems confessing to Bijou. Sabu helped him out by advising him to just keep on trying, as he apparently did with Françoise. Boss later runs off to find Sabu so he can travel with him and "become a real man" for Bijou. Of course, Hamtaro quickly finds him and drags him back to the Clubhouse. Boss then is happy whenever they see Sabu again.
Boss has a huge crush on Bijou. However, she is unaware of this. She attributes the attention he pays her to simple generosity. She does care about Boss and values his friendship, but he is more like a brother to her. Boss sparks many attempts to win her over, even if some mean risking seasickness. Boss’s crush on Bijou diminishes as the series goes on.
In Bonjour, Oshare!, Oshare seems to have feelings for Boss when he shows her what Japan is all about, as she apparently has some sort of infatuation for Japanese people, or at least samurais, judging off the episode. Boss, of course, embraces this and spends the rest of the episode pondering over whether or not he should return the feelings he assumes she has. He starts to feel bad for liking Oshare after instead of having a crush on Bijou for so long. Oshare later in the episode says that she is in love with another hamster, Shinka, back home in France, to which Boss is sad but perhaps also relieved. In Non Non, Oshare! she returns once more and says that her relationship with Shinka was "meaningless love" and that she is in love with another ham now. In A Valentine Battle! she is back and is in love with yet another hamster, this time: Hamtaro. Boss assumes at first that she is talking about him, but alas this is not the case, thus ending the crush.
In Fluffy Gelato, she takes an immediate shine to Boss when she is impressed by his berry-picking skills. Gelato and Boss play for a while and he shows her his house, to which he is delighted that a princess wants to see his house (or at least she claims to be a princess). She seems in love with him from the start, and when they regroup with the rest of the Ham-Hams, Gelato announces that they are in love and that Boss will become her prince, to which Boss is ecstatic. They play happily for the rest of the day and Boss even rescues her and her beloved spoon from a crow. When Gelato returns home (not to her “palace”, but to an ice-cream van run by her owner), she says to Boss she won't ever forget her prince. Boss is very upset when she leaves. This is the first time a girl hamster returns Boss's feelings.
- Get Well, Laura (#16)
- Courage, Cappy! (#21)
- Merry Christmas! (#25)
- The Legend of the Courageous Hamtaro! (#26)
- The Amazing Auntie Viv (#28)
- Boss is a Mom! (#31)
- The Precious Letter! (#38)
- Even the Ham-Hams Get Seasick! (#50)
- Boss, the Cool Ham of the Sea! (#56)
- The Animal Hospital (#71)
- Boss Runs Away (#91)
- It's a Duel, Boss! (#121)
- Boss's New Room (#145)
- Bonjour, Oshare! (#190)
- I'm Parting, Clubhouse! (#193)
- It's Your Turn, Hero-Ham! (#199)
- Sweet Worm Surprise (#205)
- Here I Am, Clubhouse! (#206)
- Eternal Hero (#223)
- Boss and Shiron (#228)
- Fluffy Gelato (#252)
- Space Hams (#257)
- Boss is so Popular! (#276)
- Main article: Boss/Gallery
- His Japanese name, "Taishō", literally translates to "boss" or "leader".