Toru Suzushima is the childhood friend and fiancé of Kanako Kasugazaki. He is in Class 2-C and considered "boring" by the twins and Kyoya because he's not very sociable and, as a member of Class 2-C, his pedigree and grades aren't as sterling when compared to them.
Toru is the fiancé of Kanako, their engagement having been decided by their parents when they were very young. His family owns the Suzushima Trading Company, a top importer and exporter of fine china and tableware. Thus, he was asked by Kyoya to bring whatever he deemed particularly interesting for the Host Club whenever a shipment arrives.
Toru appears in Ep 02 - The Job of a High School Host! wherein he arrives at the salon to bring a new teaset and runs into Kanako, who is teaching Haruhi how to waltz prior to the upcoming Dance Party. Kanako is embarrassed to see him because she currently has a crush on Haruhi and is known to have the Host-Hopping disease. She denies knowing Toru after he leaves and then leaves hurriedly, herself. Honey reveals their background, which Kyoya has known from the outset but kept to himself.
On the night of the Dance Party, Kanako is dancing with Haruhi when Honey and Mori whisk Haruhi off the dance floor and into a private room where the twins make her change into girls' clothing as part of Tamaki's scheme to reunite Toru and Kanako. Haruhi enters a darkened classroom where Toru waits and Tamaki brings Kanako there, as well. Upon seeing Haruhi (as an unidentifiable girl in the dark) with Toru, Kanako flees in tears realizing her folly. Toru rushes after her and catches her, at which point he admits his feelings and asks if Kanako will wait for him while he spends some time in Europe, broadening his horizons for her sake. She agrees.
The conclusion of the episode has Kanako selected as the Queen of the Ball who will receive a kiss on the cheek from Haruhi (once again in menswear). Toru says it will mark the end of her Host-Hopping days but none of them are prepared for the unplanned event that pushes Haruhi and Kanako into a lip-lock. Even so, Toru accepts it because he's secure in his relationship with Kanako and she with him.