Sakunami is quite small in both size and build. He has large, brown eyes, straight black hair with a fringe parted in the middle, and small, thick eyebrows.
Sakunami is sincere and hardworking, taking his job as a libero very seriously.
Sakunami is first seen in the first match between Date Tech and Karasuno High, where he plays as the team's libero.
Spring High Preliminary Arc
Later on, he appears as a spectator at the Karasuno vs Johzenji High match along with Futakuchi, Aone and Obara and gives insight into how Johzenji trains, saying that the volleyball club always spends more than half of each practice session playing 2-on-2 games. On that same page, he says he has a friend on the Johzenji High basketball team, which is how he knows this.
Tokyo Nationals Arc
Sakunami played in the practice match between Date Tech and Karasuno. Later, he is shown watching Karasuno's matches with the rest of his team in the school computer lab.
Jumping Reach: 295 cm
In a flashback during the Datekou vs Aobajousai match, the coach told Sakunami that he would need to "steer" Koganegawa due to the latter's lack of technique. Sakunami is seen putting this into practice during the match, and it is also confirmed that they are in the same class, 1-A. The two also attened the 2018 Schweiden Adlers vs. MSBY Black Jackals match together.
- His favourite food is Kaki-pi.
- His current concern is that "I'd be happy if I could grow a little taller."
- Koganegawa and Sakunami are in the same class
- His star sign is Virgo.
- Kōsuke (浩輔) - Abundance of Help
- Sakunami (作並) - To Line Up
- "I'll aim my receive to go to the best spot for Koganegawa-kun!" (To himself during Date Tech's Spring High Preliminary quarterfinals match against Aoba Johsai, Volume 15 Chapter 127)