[2] In May 2019, Lei came through Q School on the overall Order of Merit to earn a two-year card on the World Snooker Tour for the 2019–20 and 2020–21 seasons.

[5][6] In March 2024, by beating Australian Vinnie Calabrese from 5‍–‍3 down to win 6‍–‍5, Lei won the 2024 APSBF Asia Pacific Open Snooker Championship to earn another two-year card on the World Snooker Tour, starting from the 2024–25 season.

[7] In December 2024, after never having advanced beyond the Last 16 of a professional tournament, Lei won the 2024 Scottish Open, defeating compatriot Wu Yize 9‍–‍5 in the final.

It was only the fourth ever all-Chinese ranking event final and the second of the 2024–25 season (after the 2024 Wuhan Open).

[2][8] On his way to the final, he defeated Shaun Murphy, Stuart Bingham, Tom Ford and Mark Allen, all in deciding frames.