Sugawara is shown to be average in height with a slender build. He has slightly thick eyebrows, light grey hair and hazel-brown eyes with a birthmark mole under his left eye. He is usually seen with a gentle smile on his face.
Being the vice-captain, he has a soothing and gentle personality for his teammates and acts as a pillar of support for them. Even though he isn't Karasuno's regular setter anymore, he does not dream of giving up on playing. As such, he encourages himself and all of his teammates to never give up, no matter how rough the situation might be.
Sugawara's dedication to volleyball is clear when he decides to continue club activities even when most third years choose to retire to focus on their futures. In a meeting, his teacher asked Sugawara why he's so determined to continue playing even though he's not a starting member, and Sugawara replied that he doesn't want to have regrets in the future.
He is also quite perceptive as he noticed how Tanaka asked for the key to the gym (back during the first years' 3-on-3 match) even though he always comes in late. He is also intelligent as he can come up with helpful tactics during games that his team members can use. An example of this is when he came up with the idea of saying "bring it" and "send it to me" for Kageyama and Hinata's combo. Suga also came up with the hand signals overnight while his teammates were sleeping.
Despite his nurturing behavior, he is sometimes mischievous, as seen from how he supports Hinata to barge into the Youth Camp uninvited. He also tends to get violent when he teases his teammates, often smacking them around when he's excited to join the game, although this does have the effect of cheering up the team as well.
He is also rather proud, although it is very rarely shown. Notable examples are when he said: "Kageyama, from here on out if you start getting bombarded by interviews, you're gonna say 'I learned everything from a magnificent senpai called Sugawara', got it?", and when he bragged about how he came up with the name of Kageyama and Hinata's new technique 'Back Minus'. During the battle with Shiratorizawa, he was so irritated by the loss of their team that he started rambling and pouting, which is very unlike his usual mature demeanor.
While on the sidelines, Sugawara pays close attention to the way the other team plays, often able to give his teammates advice on how to beat the other team. On the off-chance that Sugawara is put in the game, he can carry over what he learned from watching on the sidelines in order to rally the team and score a few points. However, he quickly gets stressed out by the heat of the game and starts to over-think things too much.
Because Sugawara rarely plays in official matches, he's an unknown element. When he is called into games, the other teams, who may have had time to study up on the usual starting line up, don't typically know what to expect from Sugawara, thus working to Karasuno's advantage.
Height and reach, as of mid-November:
- Fingertip Height: 222 cm
- Jumping Reach: 299 cm (spike) / 285 cm (block)
- Synchronized Attack: Since the summer training camp arc, Sugawara has been mostly responsible for the team's synchronized attacks. He also practiced spiking during that time and now uses that to confuse opponents in matches. In the final set of the final match against Shiratorizawa, he joins in with the rest of his team for several all-in synchronized attacks off of Yū Nishinoya's overhand tosses.
- Pinch Serves: Sugawara is often subbed in to serve in place of Hinata or Tsukishima. He isn't capable of performing a powerful spike serve or a jump floater, but he is particularly good at aiming toward difficult spots for opponents to receive through the use of a float serve. He has frequently used float serves to force opponents' spikers, such as Kentarō Kyōtani, to receive, thus slowing them down and making them unable to spike.
- Calculated One-Point Two-Setter: A synchronized attack with Sugawara as the setter and Kageyama as a spiker, giving Karasuno five (as opposed to four) available spikers.
- Favorite Food: Super spicy mapo tofu
- Current Concern: A lot of his juniors are taller than him.
- Sugawara wears white gym shoes with blue/green accents.
- He went to Nagamushi Junior High.
- He is the oldest member of the team.
- He is enrolled in a college prep class, along with Daichi.
- His star sign is Gemini.
- He, along with Daichi and Asahi, forms a set. His jersey number (2) is symbolic of his position as a setter, as a toss is usually the second contact in volleyball.
- Furudate wrote that he got Sugawara's name when "At my previous workplace, I had a senpai who got called “Suga-san”. I somehow really liked the way that sounds. I named him Sugawara to be able to call him “Suga-san”."
- In Haikyuu's first popularity poll, Sugawara placed in 4th with 5,568 votes. In the second, he placed higher at 2nd with 11,254 votes.
- Kōshi (孝支) - Supporting One's Elders
- Sugawara (菅原) - Sedge Plain