Tanaka has a shaved head with a widow's peak and sharp blue-grey eyes (golden brown in the manga colored illustrations) which lead many to mistake him as a delinquent. Back in his first year at Karasuno, Tanaka had short fuzzy hair dyed in a light color. 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.
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.
He is a player who never gives up on the ball. According to Keishin Ukai, Tanaka is the second strongest spiker in Karasuno (Asahi being the first) and most importantly, his ability to perform when he's cornered doesn't deteriorate. He shows incredible mental fortitude during games, and this mental strength gives him the qualities of an ace. Although he doesn't demonstrate it, it's been noted by Daichi that he does have pretty good game sense.
Height and reach, as of mid-November:
- Fingertip Height: 224 cm
- Jumping Reach: 324 cm (spike) / 312 cm (block)
- Inner Cross: After the Tokyo Expedition Arc, Tanaka is seen working on his inner cross. Initially, he struggles with the control, but he ultimately perfects it in a clutch moment during the Inarizaki match. His inner cross has an extremely sharp trajectory and lands across the court before the attack line.
- Straight Spike: Tanaka uses a straight spike that he executes off of a form meant to hit a cross. He tricks the blockers into thinking he will spike a cross with his run-up and spiking form. Then he spikes through the small opening left open by the blockers and the antenna on the side. Tanaka's straight requires absolute precision as the ball trajectory is extremely close to the boundary line. This straight, combined with his inner cross, makes Tanaka a formidable spiker.
- Jump Serve: Tanaka practices the jump serve just ahead of the Spring Interhigh. By Nationals, Tanaka has learned to perform a legitimate jump serve that can pressure his opponents.
- In Season 3 Episode 6, Tanaka makes a haiku: "後輩を支えてこその先輩だ, It's a senpai's job to always be there and help his precious juniors".
- Favorite Food: Melonpan
- Current Concern: He tried calling out to a lost-looking first-year girl to tell her the way to her classroom, but she started to cry.
- He is the only Karasuno member to play for the full length of every match they have had in the series.
- In the OVA, he asks his sister Saeko to drive Hinata and Kageyama to the Training Camp. When she refused at first, he counts his savings but finds that he doesn't have enough to pay for a ride. He persists in begging Saeko and even willingly kneels just to help his underclassmen. This shows just how much he cares for his teammates and underclassman.
- Tanaka wears dark grey gym shoes with black accents.
- He has exceptionally good hearing.
- His star sign is Pisces.
- Tanaka is the youngest of the second years.
- According to Hinata in the bonus story Kageyama of Class 1-3, Tanaka is to be the next ace after Asahi.
- Furudate gave him this name because "He’s Tanaka because he’s Tanaka-ish! I tried to give him a really cool name and that ended up being Ryūnosuke!"
- Kiyoko Shimizu's Seiyuu says that her personal favorite character is Tanaka.
- In Haikyuu's first popularity poll, Tanaka placed 9th with 3,384 votes. In the second, he dropped to 12th with 4,236 votes.
- Ryūnosuke (龍之介) - Assistance of a Dragon
- Tanaka (田中) - Ricefield Middle