and i have never changed
from who I was

      We first encounter Takasugi in chapter 29, speaking to Katsura Kotarou on a bridge. We find out through their exchange that Takasugi has been running from the bakufu and went into Kyoto for hiding. We learn that Takasugi is also in the terrorist business: he's a wanted man and is on the constant run from the officials. Katsura asks why Takasugi is in the area, to which our villain replies, "I heard there is a festival. I couldn't help myself, so I came." It's at this point where we find out that he's a much more potent and capable terrorist than Katsura: there's something he's got planned up his sleeve and of course, it's all for his goal of taking down the bakufu.

Wait, so why is he after the bakufu and what have they done to Takasugi to make him hate the world so much?

aw, what a cutie!       First, let's look at the little flashbacks we have of Takasugi as a child. Under the tutelage of his beloved sensei, Takasugi follows his teachings diligently and studiously (just not as studiously as Katsura). Still, we can derive that Takasugi is a rather bright child, and like Katsura, came from a rich background (which could or could not be canon, according to the black hole kotatsu episode). Having come from a rich family, we can assume that he was spoiled as a child; it could have been that he was used to having everything he could possibly want within good reason. Aside from these speculations, nothing else is known about Takasugi's family outside of the school. Thus, we can say that it was his teacher who served as the closest family member Takasugi had around.

oh boy...       As a child, Takasugi also seems to have been rowdy, possibly under the influence of Gintoki's own trouble-making personality. Takasugi has a huge confidence streak: he doesn't back down from Gintoki's trouble-making schemes and doesn't allow himself to lose in anything. This hasn't changed a bit, either. Takasugi has always been confident and to have someone who actually has the balls (this term was bound to be used eventually!) to challenge him must have been seen as fun; since Takasugi was never one to make friends easily, having Gintoki as a friend under the pretense of him being a "rival" of sorts was definitely a good improvement on his people-skills... which of course turns to shit when the Amanto come.

poor Sakamoto gets no love...      When the Amanto arrive and the government move to take their teacher away, his students rally for action. It is during the Joui war that Takasugi leads the anti-Amanto faction known as the Kiheitai, where he fights alongside Gintoki, Katsura and Sakamoto. In chapter 393, we learn about the Kansai Purge, where many of the samurai fighting in the Jouishishi war were hunted down relentlessly. However, their determination to try and save their teacher aided Takasugi, Gintoki and Katsura in their battle, with their sheer power rendering them impossible to capture. But despite their efforts, their teacher became irrevocably lost to them, and it is Sadasada, the shogun at that time, and the Tendoushuu, who were behind their teacher's capture and death.