[2] She would practise the sport for between five and six hours daily; in one of her practice routines, Ng would cue through a small ring placed on the table to help assess her accuracy.

[10] Ng's first experience of an international snooker competition was at the 2006 IBSF Women's Championship in Amman, Jordan,[3] where she won three of her eight matches in the qualifying group, winning 13 frames and losing 16.

[a][17] Ng lost her quarter-final match 2–3 to Bi Zhu Qing at the 2007 Asian Indoor Games in Macau in November 2008.

[5] In the final, Ng produced some impressive long potting and defeated Kathy Parashis, a 10-time winner of the Australian Open, 5–1.

When Ng was leading 3–1, the players were summoned to drug tests and returned to take the remaining frame she required to win the match, becoming the youngest-ever IBSF women's champion at the age of 19.

[26] At the 2010 Asian Games, Ng won the gold medal as a member of the women's six-red snooker team, along with So Man Yan and Jaique Ip.

[30] On 15 December 2010, Ng successfully defended her IBSF World Snooker Championship title in Syria, defeating compatriot Jaique Ip 5–0 in the final.

[33] She then defeated Eslami Taherh 4–0 in the last 16, Anuja Chandra 4–3 in the quarter-finals—the only match in which Ng lost any frames—and Vidya Pillai 4–0 in the semi-finals.

[39] Ng won a silver medal at the 2013 Asian Indoor and Martial Arts Games in Six-red snooker in July, losing 3–4 to Amornrat Uamduang in the final.

Ng emerged from the qualifying groups in fourth place overall[53] and defeated Arantxa Sanchis 4–0 and Amee Kamani 4–1 to reach the final.

[56][57] Ng and her playing partner Katrina Wan Ka Kai won the 2016 World Women's Snooker pairs title by defeating Maria Catalano and Tatjana Vasiljeva 4–1 in the final.

[58] At the 2016 World Ladies Snooker Championship, the top-eight seeds, including defending champion Ng, were placed in the knockout and each faced a qualifier.

[60] With Katrina Wan, Ng won the IBSF World Six-reds snooker team tournament in Sharm-El-Sheikh, Egypt, with a 4–3 victory over Vidya Pillai and Amee Kamani of India in the final.

Fifteen minutes after the conclusion of the team final, Ng played Pillai in a quarter-final match of the singles and lost 2–4.

After winning all three matches in her qualifying group 3–0, Ng won the deciding frame 4–3 against Irina Gorbataya in the last 16, having trailed 1–3.

[62][63] At the first Asian Billiard Sports Championships, which was held in 2016 in the United Arab Emirates, Ng defeated Arantxa Sanchis 5–1 in the semi-finals and Vidya Pillai 5–1 in the final to gain the title.

[66] In 2017, Ng supported the Hong Kong Women's Foundation campaign #MyRealCareerLine, which was set up to tackle sexism and gender inequality at work.

[67][68] The 2017 World Women's Snooker Championship was held in Singapore, marking the first time in over 20 years the tournament had taken place outside the United Kingdom.

In the knockout stage, Ng defeated Pui Ying Mini Chu 4–0 in the last 16 and Waratthanun Sukritthanes 4–3 in the quarter-finals.

[75] Ng was seeded into the last 16 at the 2017 Paul Hunter Women's Classic in Fürth, Germany; she reached the semi-finals without losing a frame, defeating both Inese Lukashevska and Diana Stateczny 4–0.

[76][77] On reaching the quarter-finals of the WLBSA British Open in Stourbridge, England, in February 2018, Ng became the first Asian player to top the women's rankings.

[79] Ng successfully defended her world championship title, without conceding a frame, at the 2018 tournament held at St. Paul's Bay, Malta.

[80][81] Ng emerged from the qualifying stage with 3–0 wins over Judy Dangerfield, Katarzyna Bialik, and Ronda Sheldreck, and was seeded into the quarter-finals, where she defeated Wendy Jans 4–0.

[85] Ng took the 2018 LITEtask UK Women's Championship title in September, defeating Suzie Opacic 3–2, Ploychompoo Laokiatphong 3–0, and Jaique Ip 4–0.

[90][91] Ng reached the final of the 2019 Belgian Women's Open with wins of 3–0 over Jane O'Neill and Emma Parker, and of 4–3 over Nutcharut Wongharuthai in the semi-finals.

[94] She was also defeated by Wongharuthai 4–1 at the quarter-finals stage of the 2019 World Women's Snooker Championship,[95] making 2019 the first year since 2012 that Ng had not reached at least the semi-finals of the tournament.

[97] In April 2019, Ng played Alan McManus in the first round of qualifying at the World Snooker Championship – after winning the first two frames, she eventually lost the match 6–10.

[98] She was runner-up in the 2019 Women's Tour Championship, held at the Crucible Theatre, defeating Rebecca Kenna 2–0 in the semi-finals before losing the one-frame final to Reanne Evans.

[99] At the Australian Women's Open in 2019, Ng and Nutcharut Wongharuthai were the only two players to complete their qualifying groups without losing a frame.

[103] Ng finished top of the qualifying round, winning all four of her matches 2–0,[104] before defeating Joy Lyn Willenberg 3–0 in the last 16, and Amee Kamani 4–1 in the quarter-finals.