2017 In July, Leong won the
Asian Junior Championships by defeating Bai Yupeng in the final. In October, he reached the final of
World Junior Championships where he lost to top seed,
Kunlavut Vitidsarn, 21–17, 15–21, 9–21. In November, he reached his maiden senior final at the
Malaysia International Challenge before losing to compatriot
Iskandar Zulkarnain Zainuddin.
2018 In January, he reached the final of the
Thailand Masters as a qualifier where he lost to the second seed,
Tommy Sugiarto. In April, he won his first senior title at the
Finnish Open by defeating his compatriot
Cheam June Wei in the final.
2019–2020 In December 2019, Leong reached his first final of the year at the
Bangladesh International but lost out to top seed
Lakshya Sen. He was part of Malaysia's men's team that won silver at the
2020 Asian Team Championships in February 2020.
2022 Leong was one of the players that won gold at the
2022 Asian Team Championships for Malaysia in February. In October, he clinched his first BWF World Tour title at the
Indonesia Masters, beating compatriot Cheam June Wei in three games.
2023 In May, Leong made his debut at the
2023 SEA Games where he helped Malaysia win a silver medal in the
men's team event. He later competed in the
men's singles event and went on to win bronze, losing out to Indonesia's
Christian Adinata in the semi-finals. In July, he was crowned as men's singles national champion after winning the
2023 Malaysian National Badminton Championships. In October, he competed at the
KL Masters as the second seed. He emerged as the winner after defeating top seed
Lee Chia-hao 22–20, 21–13 in the final.
2024 In November, Leong reached the final of the
Japan Masters, his first of a Super 500 level tournament. He finished as the runner-up, losing 10–21, 13–21 to
Li Shifeng.
2025 In 2025, Leong participated in the
SEA Games in Thailand. He won a silver medal in the team event and a bronze in the men's singles, repeating his achievements from 2 years earlier in Cambodia. == Achievements ==