Tsuyoshi first appeared when Tsunayoshi Sawada ate at TakeSushi with Reborn, Bianchi and Lambo, who did a "dine and dash", meaning that they ate without paying for the meal, forcing Tsuna to work at TakeSushi for a while to pay off their debt.
When Tsuna was hospitalized because of his injuries from Death Mountain, Yamamoto came to his hospital room for support. He decides to bring Tsuyoshi, his dad. Tsuyoshi brought a big green bag with his sushi-making table inside and his small blue bag with supplies and food like his knife and fish. Tsuyoshi made authentic Japanese sushi for Tsuna. Tsuyoshi left the room to go back to his shop and told his son to take care of the rest.
When everyone arrived in the future, they were informed by Reborn that Tsuyoshi was killed by the Millefiore Famiglia. However, after Tsuna defeated Byakuran, they were told that the future changed and all disasters caused by Byakuran and the Millefiore would be undone; thus, Tsuyoshi would still be alive.