First of all, I have a problem writing his name, as it can be written with "Oo", "Ou" and "Oh". All of them are correct, so I just stick with Ohtsuka, as it is written in Anime News Network, even though I personally despise that "oh" for long o. (In Word, I only use macrons, but it's quite difficult to play with it here.)
Houchuu Ohtsuka was born in 1954, May 19, and his hometown is Okayama. He seems to be a healthy living person; well, at least his hobbies are different sports discipline. He has a characteristic voice and manner of speach, and you simply cannot mistake him for anyone else. I've heard him in numerous anime, although here I present only a few of his roles. Apart from starring in anime, he also performs in live-action films; notably, he voiced over Aragorn in "Lord of the Rings" trilogy... as well as Merry in "The Lord of the Rings" animation from 1978 ^^
I may have heard him already before, but it was only "Naruto" and his role of Jiraiya that I started to pay attention to his voice. Not to mention I admire Jiraiya very much, he is simply wonderfully played, and Ohtsuka's voice fits that character perfectly. He can be very positive, very solemn... or theatrical if needed. He is splendid for wise characters with sense of humour... and ability to show off ^^
Ohtsuka stars in that mad house that is "Arakawa: Under the Bridge", and he portrays Shiro. He also appears in the current series of "Durarara!", playing a mafia boss (or something) Haruya Shiki. However, most of all I admire him as Abuto in "Gintama". Abuto is second-in-command of Yato mercenaries boss, Kamui. Outwardly, Abuto seems completely bored with his job and constantly complains about his "stupid commander". In truth, he cares about Kamui deeply and supports him in every situation. Also, I wouldn't call Abuto typical Yato; opposed to Kamui, who is a bloodthirsty beast, he is much calmer and able to see and appreciate more things that just fighting and killing. Sometimes I feel he doesn't really fit them, but then again, it's the best reason he sticks with someone like Kamui.
However, it's not that Ohtsuka plays only good and bright guys. He is pretty wicked as Cleitus in "Reign: The Conqueror", evil as Hollow Metastacia in "Bleach", and dangerous as Proxy One in "Ergo Proxy", an alter ego of the main hero Vincent Law. It is not with laugh that he portrays those characters.
As I mentioned, I heard him in many more anime, like "Neon Genesis Evangelion", "Noir", "Yami no matsuei", "Cowboy Bepop", "Saint Seiya", "Rurouni Kenshin", "Samurai Champloo", "Spice and Wolf", "Vampire Hunter D", "Legend of the Galactic Heroes", "Kenyuu Densetsu Yaiba", "Tiger and Bunny", but those roles had little impact on me, so I leave them undescribed. However, it's always a nice thing to hear Ohtsuka, for I simply like his voice and admire the way he often speaks :)