2022: Major doubles debut Quinn won the doubles at the
2022 USTA Boys 18s National Championship with his partner
Nicholas Godsick which earned them a wildcard into the main draw of the
2022 US Open. They won the final with a 6–4, 6–0 defeat of
Sebastian Gorzny and
Alex Michelsen who had been top seeds following their
2022 Wimbledon Junior doubles victory. In the singles event at the same competition, Quinn also reached the final but lost to
Learner Tien in 4 sets. For reaching the final, Quinn gained a wildcard into the
singles qualifying at Flushing Meadow.
2023: Turned Pro, Major singles debut, first ATP win After winning the 2023 NCAA Singles Championship in May 2023, Quinn turned professional one month later. At the
US Open, he entered as a wildcard entry all three of the events he was eligible for: he lost in the first round of the
men's singles and
men's doubles, but he and partner
Ashlyn Krueger made it to the second round of the
mixed doubles.
2024: Masters debut Quinn received a wildcard at the
2024 Dallas Open for his debut at the tournament. Having also received a wildcard for the qualifying event for the
2024 BNP Paribas Open in Indian Wells, Quinn qualified for the main draw, making his Masters debut. Quinn recorded his second ATP Tour win at the
2024 Hall of Fame Open over
Marc Polmans, having recorded his first one at the same tournament in
2023 over
Mukund Sasikumar also as a wildcard. At the
US Open Quinn lost to
Valentin Royer in the second round of qualifying but reached a new career-high ranking of No. 236 on 26 August 2024.
2025: French Open third round, top 100 Following reaching the final at the
2025 Canberra Tennis International as a qualifier, Quinn entered the top 160 in the singles rankings on 27 January 2025. and also for the main draw in
Miami. In April, Quinn reached the main draw at the
2025 Barcelona Open Banc Sabadell, and also qualified for his next Masters 1000 main draw at the
2025 Mutua Madrid Open, where he defeated fellow qualifier
Dušan Lajović. Ranked No. 106 at the
2025 French Open, Quinn recorded his first Grand Slam main draw wins, after qualifying, over
Grigor Dimitrov by retirement, and over lucky loser
Alexander Shevchenko in five sets, to reach a major third round for the first time in his career. As a result he entered the top 100 in the singles rankings on 9 June 2025. At the
2025 Wimbledon Championships he recorded a first-round win over 2023 Wimbledon junior champion
Henry Searle.
2026: Major third round, Challenger 175 title, top 50 Making his debut at the
2026 Australian Open in January, Quinn reached the third round with two straight sets wins defeating 23rd seed
Tallon Griekspoor and
Hubert Hurkacz. The following month, he made his
Davis Cup debut for the United States with a victory against
Fabian Marozsan of Hungary. In March, Quinn played in
Indian Wells, where he lost in the first round to compatriot
Reilly Opelka. With this early defeat, he took part at the
Arizona Tennis Classic in
Phoenix – a
Challenger 175 event – the following week. The young American lifted the biggest title of his career with wins over alternate
Billy Harris, and in an all-American final, over seventh seed
Marcos Giron. ==Style of play==