2010

Lee captured the attention of Hong Kong when she won gold at the 500-meter time trial track cycling event at the 2010 Asian Games,^[12] in which she broke the Asian Record in winning the championship with a time of 33.945 s.^[13] Lee also won a bronze in the sprint event.^[14] In December 2010, Lee improved her Asian Record in 500-meter time trial with a time of 33.939 s in the 2010 Melbourne Track Cycling World Cup.^[15] Lee's performance has impressed the cycling hierarchy, and she received the Hong Kong Potential Sports Stars Awards for 2010.^[16] She also received the Medal of Honour from the Hong Kong Government in 2011 for her outstanding achievements in international cycling competitions.^[2]

2012

In February 2012 at the 2012 London Track Cycling World Cup, Lee upset Olympic champion Victoria Pendleton to win a bronze medal in the sprint event at the London Velodrome. She beat Pendleton 2–1 after losing to eventual champion Guo Shuang of China in the semi-finals.^[17] Lee also won a silver in the keirin final. The Union Cycliste Internationale described 24-year-old Lee as "a late revelation in the sprint events" after she claimed her second medal.^[18]

Lee was chosen as the flag bearer of the Hong Kong Olympic Representatives for the 2012 Summer Olympics in London.^[19][20] She won the bronze medal in women's keirin.^[21] Lee's bronze medal feat handed Hong Kong their first ever Olympic medal in cycling, and only their third overall.^[22][23] Lee also participated in the women's sprint event although she did not progress through the 1/8 Finals after losing to Cuba's Lisandra Guerra. Lee eventually finished at the 10th place.^[24] Lee received HK$ 750k from the Hang Seng Athlete Incentive Awards Scheme for her achievement in the Games.^[25] In an interview with Ming Pao, Lee said she hoped her achievement in the London Olympics can inspire a new generation of Hong Kong athletes for the 2016 Olympic Games.^[26] She loved cycling but she is going to retire soon.

2013

After the Olympics, Lee had a perfect start in the 2012–13 World Cup opening series with a gold medal in the women's sprint in Cali, Colombia, which is her first victory in a World Cup event.^[27] This is followed by a bronze in women's keirin in the second leg, which was held in Glasgow, Scotland.^[28] Lee won her first medal in 2013 by coming third in the women's sprint event in the third leg of the 2012–13 World Cup series.^[29]

In February 2013, Lee carried on her good form and won gold in the women's 500m time-trial at the World Track Championships in Belarus.^[30][31] She became the first female and third overall athlete from Hong Kong to wear rainbow jersey. After the gold, Lee beat Guo Shuang of China in Women's Sprint and won a bronze medal, securing her second medal in Minsk. This is the first time any HK athlete won multiple medals at a World Championship event.

2014

At the 2014 Asian Games, she won gold medals in Keirin and Sprint. She also won gold in at the Asian Cycling Championships for Keirin and 500m time-trial, plus a bronze in Sprint.

2016

At the 2016 Summer Olympics, in the keirin competition, she advanced to second round after coming in first in her heat. However, in the second round, she crashed after colliding with Anna Meares of Australia and could not finish the race.^[32] She was placed 7th in the competition. On the next day, despite still nursing her injuries from her crash from yesterday, she competed in the sprint competition. She won in first and second rounds but lost to Kristina Vogel of Germany in the quarterfinals. She finished 6th in this competition.

2018

Lee successfully defended her title in Keirin and 200m time-trial at the 2018 Asian Games.

2019

In 2019 UCI Track Cycling World Championships, Lee claimed gold in sprint and keirin. She became the only athlete from Hong Kong to earn multiple rainbow jerseys.

2021

At the 2020 Summer Olympics, Lee competed in both sprint and Keirin. In the keirin event, she lost in her heat in the first round but won in the repechage to advance to quarterfinals. She finished first in her quarterfinal heat to advance to the semifinals. However, she finished 5th in her heat and competed in the B Final for placement. She finished 8th overall in this event. In the sprint event, Lee advanced to 1/16 finals but lost to Katy Marchant of Great Britain to fall into the repechage. She won in the repechage and advanced to 1/8 final. She won in 1/8 final and quarterfinal. In the semifinals, she lost to Olena Starikova from Ukraine and had to race in the bronze medal match against the reigning world champion Emma Hinze of Germany. She won the bronze medal match^[32] and became the only Hong Kong Olympian with medals from different Olympic Games.