Ryūnosuke Tanaka (Japanese: 田中たなか 龍之介りゅうのすけ Tanaka Ryūnosuke) for the majority of the series was a second-year student and wing spiker on the Karasuno's boys volleyball team and was its up-and-coming ace.
After graduating high school, he became a personal trainer and married Kiyoko Shimizu.

Tanaka has a shaved head with a widow's peak and sharp blue-grey eyes (golden brown in the manga colored illustrations) which led many to mistake him as a delinquent. Back in his first year at Karasuno, Tanaka had short fuzzy hair dyed in a light color (blond in the anime). He is average in height and has a lean, but strong build. He tends to make intimidating faces to try to scare others, which Daichi scolds him for.

Post-timeskip, Tanaka appears to have a bit more of a muscular build that most likely resulted from his career and also has let his hair grow out a bit in its natural dark color.

Loud, hot-headed, and easily angered, he is no stranger to picking fights. He is also somewhat of a slacker, shown by his less-than-stellar work ethic in school and his usual lateness to practices. Despite all this, he is shown to be caring and supportive of his teammates, and even protective of his underclassmen. Tanaka doesn't take kindly to people who belittle others, as shown when he grows upset at Kei Tsukishima for trash-talking others during their first 3-on-3 match. In addition, he gets very excited and is easily won over when an underclassman calls him "senpai".

Once he gets fired up, he is usually unstoppable on the court and also uncontrollably loud, as demonstrated by his over-the-top cheering after he scores or pulls off an incredible move. He also has the tendency to take off his shirt and spin it over his head when he scores a point in practices.

Tanaka is also someone with strong mental fortitude, not letting himself be brought down by things like being targeted or getting blocked during games. He seems to know that he can be an easy target to some people and has a lot to improve on, but instead of letting those things bother him he gets fired up and keeps trying no matter what. However, even for Tanaka, things can be too much and every six months or so he starts to think he is nothing but mediocre. But, he tells himself that thinking like that is just a waste of time.

Tanaka has a large interest in girls, as shown in the numerous posters of female idols that are posted up in his room. One girl in particular who he has a large interest in is Kiyoko Shimizu. He often approaches her and tries to talk to her, though his advances are usually ignored, which he claims turns him on. Tanaka usually looks out for her, alongside Nishinoya, especially during the Tokyo training camp and official matches when other teams take an interest in her.