2023: First Challenger title Walton won his maiden
ATP Challenger doubles title at the
San Luis Open Challenger with
Colin Sinclair. He won his first singles Challenger in August at the
Atlantic Tire Championships in Cary, North Carolina.
2024: Major debut, top-100 For his Grand Slam main-draw debut, he received a wildcard for the
Australian Open, but lost to
Matteo Arnaldi in the first round. Ranked No. 150, he qualified for the
Miami Open making his Masters debut, losing in the first round to
Félix Auger-Aliassime. Following his third singles title at the
Taipei Challenger, with a win over
Illya Marchenko he reached the top-100 at world No. 95 on 20 May 2024. Walton received a wildcard entry for the
French Open, but lost to
Arthur Rinderknech in the first round. He recorded his first ATP main-draw win at the
Mallorca Championships defeating
Yannick Hanfmann,before losing to
Paul Jubb in the second round. He qualified
Wimbledon making his debut and recorded his first Major win over
Federico Coria, before losing to
Francisco Comesaña in the second round.
2025: Miami fourth round, first ATP semifinal At the
Australian Open, where he gained direct entry into the main-draw due to his ranking, Walton lost in the first round to
Quentin Halys in five sets. In March at the
Indian Wells Open, he defeated
Giulio Zeppieri for first at the Masters-level win, before losing to 27th seed
Denis Shapovalov in the second round. At the
2025 Miami Open, where he entered the main-draw as a lucky loser directly into the second round, replacing
Hubert Hurkacz after his late withdrawal, Walton defeated
Luciano Darderi and wildcard entrant
Coleman Wong to reach his first Masters fourth round, at which point he lost to third seed
Taylor Fritz. In July, Walton reached his first ATP Tour semifinal at the
2025 Los Cabos Open. He lost to third seed Denis Shapovalov in the semifinal. At the
Cincinnati Open, he defeated qualifier
Mariano Navone and12th seed
Daniil Medvedev to make it into the third round, where his run was ended by 22nd seed
Jiří Lehečka.
2026: Two Masters second rounds At the
Australian Open, Walton lost to world No. 1 and eventual champion
Carlos Alcaraz in the first round. In March, reached back-to-back Masters' tournament second rounds at
Indian Wells, where he defeated Quentin Halysand before losing to 25th seed
Learner Tien, followed by the
Miami Open, where he qualified and overcame
Sebastián Báez and then lost to 12th seed
Jakub Menšík. ==ATP Challenger and ITF Tour finals==