After not seeing competition in April 2017, Ruusuvuori returned in May, participating in the Italy F13 Futures event, where he lost in the third round of singles qualifying. He then competed in the 58th Trofeo Bonfiglio junior event, losing in the first round of both singles and doubles. In June, he competed further in both Juniors and Futures events. He competed in both the boys' singles and doubles at the French Open. In singles, he lost in the first round, again losing to Moutet. Along with partner Rudolf Molleker of Germany, Ruusuvuori was seeded fifth in doubles. Together they reached the quarterfinals, losing to eventual finalists Vasil Kirkov and Danny Thomas of the United States. He then competed in the Portugal F9 Futures, winning three rounds in singles qualifying before reaching the quarterfinals. In July, Ruusuvuori competed in two events on the junior tour. Competing at the Nike Junior International in Roehampton, he reached the semifinals in singles and first round in doubles, again partnering Molleker. At Wimbledon, he faced Molleker in the first round of singles, retiring in the second set. He returned to competition in August at Les Internationaux de Tennis Junior Banque Nationale du Canada, losing to Brian Shi of the United States in the second round. Competing as an unseeded player at the 2017 US Open in September, Ruusuvuori saw his best singles Grand Slam result of the year, reaching the semifinals. En route, he defeated two seeded players: 13th seed Sebastian Korda of the United States in the second round and 10th seed Sebastián Báez of Argentina in the quarterfinals. In the semifinals, Ruusuvuori lost to eventual champion Wu Yibing of China in three sets, 6–4, 3–6, 6–7(4), after having two match points. With Simon Carr of Ireland, he reached the second round in doubles. October saw further Futures competition as well as the final junior competition of the year for Ruusuvuori. At the Sweden F4 Futures, he again reached the singles quarterfinals after passing through qualifying, losing to eventual champion Tallon Griekspoor of the Netherlands. At the ITF Junior Masters, he finished with a 2–1 record in round robin competition, winning matches against Jurij Rodionov of Austria and Marko Miladinović of Serbia while losing to Wu for the second time that year. Reaching the final, he again faced Wu, this time exacting revenge to come out on top in three sets, 3–6, 6–1, 7–6(4),