2017: ATP debut and first win in doubles Hüsler made his ATP main-draw doubles debut at the
Swiss Indoors tournament, where he partnered former world No 1.
Nenad Zimonjić, having received a wildcard into the tournament. The pair defeated
Adrian Mannarino and
Benoît Paire to give Hüsler a win in his first tour-level match, before losing in the quarterfinals to
Marcus Daniell and
Dominic Inglot.
2018: Challenger doubles title, ATP singles debut & first win Hüsler claimed his first
ATP Challenger Tour doubles title in his first final, partnering
Sem Verbeek at the
Winnipeg Challenger. Just over a week later, Hüsler made his ATP Tour singles main-draw debut at the
Swiss Open Gstaad, where he recorded his first ATP win defeating former top-10 player
Nicolás Almagro in a third-set tiebreaker in the first round, before losing to
Facundo Bagnis in the second round. Hüsler received a wildcard into the doubles draw for the
Swiss Indoors for the second consecutive year, this time with Verbeek as his partner. The pair upset
Michael Venus and
Raven Klaasen, the top seeds for the tournament and world No. 7 doubles partnership in the
2018 Doubles Team Race Rankings in the first round.
2019: First Challenger singles title & top 300 On April 21, 2019, Hüsler won his first Challenger title at the
2019 San Luis Open Challenger Tour by beating Adrian Menendez-Maceiras 7–5, 7–6 in the final. As a result, he moved 70 positions up into the top 300 on 22 April at world No. 281 in singles.
2020: Two Challenger titles, ATP semifinals & top 150 debut Hüsler reached the semifinals of the
Austrian Open Kitzbühel, where he beat world No. 12
Fabio Fognini in the second round. As a result, he reached the top 150 at world No. 149 on 9 November 2020.
2021: Maiden ATP title in doubles He won his maiden ATP doubles title at the
2021 Swiss Open Gstaad, partnering
Dominic Stricker, defeating Polish pair
Szymon Walków and
Jan Zieliński. In September, partnering also with Stricker, he reached the final of the
2021 Challenger Biel/Bienne, Switzerland but withdrew. As a result, he reached a month later a new career-high doubles ranking of World No. 132 on 25 October 2021. He also reached the final in singles, where he lost to
Liam Broady but climbed to No. 155 on 18 October 2021. He finished the year ranked No. 188 in singles.
2022: Major & Masters debuts, Swiss No. 1, First ATP singles title Hüsler started his 2022 season at the
Traralgon International. Seeded ninth, he lost in the third round to eighth seed
Mikhail Kukushkin. In April, he won two more Challenger titles in Mexico. As a result, he reached a career-high ranking of No. 121 on 9 May 2022. In June, at the
2022 Halle Open he qualified for his first ATP 500 tournament but lost to
Mackenzie McDonald. Hüsler made his Grand Slam debut after qualifying for
Wimbledon, where he lost to lucky loser
Hugo Grenier, who was also making his debut, in the first round in five sets. |thumb|Hüsler at the
2022 French Open At the
Swedish Open, he defeated seventh seed
Holger Rune in the first round before losing to
Laslo Djere. As a result, he reached the top 100 at world No. 99 on 18 July 2022. He became the Swiss No. 1 player until 8 August 2022. At the
Winston-Salem Open, he reached only his second career quarterfinal as a qualifier after getting a second-round bye after seventh seed
Sebastián Báez withdrew, defeating previous year finalist and wildcard
Mikael Ymer and defending champion and eleventh seed
Ilya Ivashka. Next, he reached the semifinals for the second time ever in his career defeating thirteenth seed
Jack Draper in straight sets. He was only the fourth qualifier to reach the tournament semifinals ever. He lost again to
Laslo Đere in the semifinal. As a result, he reached a new career-high ranking of No. 85 becoming again the Swiss No. 1 player on 29 August 2022. At the
2022 Sofia Open, he reached his first ATP final with a win over fourth seed
Lorenzo Musetti. He defeated again fifth seed Holger Rune to win his maiden ATP title. As a result, he climbed 31 spots to a new career-high of No. 64 in the rankings on 3 October 2022. He made his Masters 1000 debut at the
2022 Rolex Paris Masters after defeating
Hugo Gaston and
Laslo Djere in qualifying. On his debut, he defeated 11th seed
Jannik Sinner in his first-round match. He lost to
Karen Khachanov in the second round. As a result, he reached a career-high ranking of world No. 58 on 7 November 2022.
2023: United Cup & Top 50 debuts Hüsler started his 2023 season by representing Switzerland at the first edition of the
United Cup. Switzerland was in Group B alongside Kazakhstan and Poland. Against Kazakhstan, he beat
Timofey Skatov. With
Jil Teichmann, they defeated
Zhibek Kulambayeva and
Alexander Bublik to sweep Kazakhstan 5–0. Against Poland, he beat
Daniel Michalski. In doubles, he and
Belinda Bencic defeated
Alicja Rosolska and
Kacper Żuk. Poland ended up winning the tie over Switzerland 3–2. Switzerland was ultimately eliminated from the United Cup and ended second in Group B. At the
Adelaide International 2, he beat the previous year finalist,
Arthur Rinderknech, in the first round. He was defeated in the second round by third seed and world No. 20,
Karen Khachanov. At the
Australian Open, he lost in a five-set battle in the first round to Australian wildcard
John Millman. He reached the top 50 at world No. 49 following the Australian Open on 6 February 2023. Representing Switzerland in the
Davis Cup tie against Germany, he won his first match over
Oscar Otte. In his second match, he beat world No. 14
Alexander Zverev. Switzerland ended up winning the tie over Germany 3–2 to advance to the Davis Cup Finals. At the
Open Sud de France, he was beaten in the second round by top seed and world No. 9,
Holger Rune. In
Rotterdam, he lost in the first round to Dutch wildcard
Gijs Brouwer. Seeded eighth at the
Open 13 Provence, he was defeated in the first round by
Grégoire Barrère. In
Dubai, he lost in the first round to
Lorenzo Sonego. In March 2023, Hüsler made his debut at the
BNP Paribas Open. He was eliminated from the tournament in the first round by
Pedro Martínez. Seeded sixth at the
Arizona Classic, he lost in the second round to qualifier and eventual finalist,
Alexander Shevchenko. In
Miami, also on his debut, he won his first round match over
Albert Ramos Viñolas before losing in the second round to 16th seed and world No. 19,
Tommy Paul. Hüsler started his clay court season at the
2023 Mexico City Open. As the top seed and the defending champion, he lost in the second round to qualifier
Federico Gaio. At the
Monte-Carlo Masters, he was defeated in the first round by
Jaume Munar. Seeded eighth at the
BMW Open in Munich, he lost in the second round to
Dominic Thiem. In
Madrid, he fell in his first-round match to
Cristian Garín. At the
Italian Open, he lost in the first round to
Jason Kubler in three sets, despite having a 7–6(6), 3–0 lead in the match. Hüsler played his final tournament before Roland Garros at the
2023 Geneva Open. He was defeated in the first round by
Wu Yibing in three sets, despite having match point in the third-set tiebreaker. At the
2023 French Open, he lost in the first round to
Daniel Altmaier in straight sets. Hüsler started his grass court season at the
2023 Libéma Open in 's-Hertogenbosch. He marked his debut at this tournament by upsetting eighth seed
Maxime Cressy in the first round. This was his first tour-level win on grass. He lost in five sets at the
2023 Wimbledon Championships to world No. 116, lucky loser and Wimbledon debutant
Yosuke Watanuki, after being two sets to love up, in a close to a four hours match that was suspended due to darkness. He suffered another tough first round five sets loss also from two sets to love up at the
2023 US Open, to world No. 16
Hubert Hurkacz and subsequently dropped out of the top 150 in October 2023, after a string of first round losses, more than a 100 positions down from his career high in February 2023. Ranked No. 200, at the
2023 Sofia Open, where he was the defending champion, he qualified for the main draw.
2024-2026: Rankings drop, out of top 250 He further dropped to world No. 237 in the rankings on 1 April 2024, close to 200 positions from his singles career-high a year earlier. In mid-April 2024, he qualified for the main draw of the
2024 BMW Open in Munich and defeated two Germans, wildcard
Marko Topo and
Yannick Hanfmann to reach his first quarterfinal in more than a year. He lost to defending champion
Holger Rune in straight sets. Hüsler qualified at the
2024 Libéma Open in 's-Hertogenbosch but lost to
Roberto Bautista Agut. He returned to the top 200 on 5 August 2024, and to the top 165 two weeks later, raising 40 positions up from No. 205, following lifting his sixth Challenger title at the
2024 Kozerki Open in Grodzisk Mazowiecki, Poland. He won his seventh ATP Tour Challenger title at the
2025 Morelos Open. It was his fourth Challenger title in Mexico. He returned to the top 150 at No. 142 on 7 April 2025 but dropped again out of the top 250 on 29 September 2025. ==Davis Cup==