[13] Su was first exposed to track and field training in middle school, after being scouted by his PE teacher who saw him touching the basketball board with ease while being only 1.50 m (4 ft 11 in) tall.

Su was passed on and deemed an untalented sprinter in numerous occasions by the coaches of the city-level track and field team.

[14] It was also during middle school that Su met his wife Yanfang Lin, whom he described as "his life-long best friend and love of his life.

His first professional track coach and mentor Yuan Guoqiang was the first Chinese 100m national record holder in the early 80s at the start of digital-timing era and was a short (5'6) sprinter himself.

[19] He was selected for the relay at the 2009 Asian Athletics Championships and won a silver medal alongside Guo Fan, Liang Jiahong and Zhang Peimeng.

On 10 August 2013, Su raced in the sixth heat of the first round in the 100 metres, subsequently qualifying to the semi-finals by clocking 10.16 seconds.

[32] The aim was to change his entire 100m pace and allow him suffer from less de-acceleration after the first 60m while maintaining his advantage at explosive start in the first half of the race.

At the beginning of his transition to change starting leg, Su was for a time even slower out of block than a female sprinter when he trained at IMF Academy after he returned to USA.

Yuan Guoqiang said that Su was so obsessed with perfecting his start at the time that he would work on his block start even when he was taking a walk, woke up in the middle of the night and contemplated why he couldn't perform the move as well as other world class athletes, and he would proceed to discuss the matter with his teammate Xie Zhenye.

[35] On 29 August 2015, Su raced with his teammates Mo Youxue, Xie Zhenye and Zhang Peimeng in the 4 × 100 metres relay.

Running the third leg, Su aided his team to a third-place finish in the heats, qualifying them for the final with a then Asian record time of 37.92 seconds.

In the final, the Chinese team crossed the line in third behind the United States and Jamaica in 38.01 seconds, giving them a Bronze Medal finish.

However, subsequent disqualification of the United States due to improper baton exchange meant that the Chinese team were promoted to a Silver medal finish in the Bird's Nest Stadium; with their Bronze being awarded to Canada.

On 26 May 2016, Su finished seventh in 100 metres at the 2016 Prefontaine Classic in a wind-aided 10.04 seconds, unable to repeat the success he had on the same track the year before.

4 days later, on 18 August 2016, Su raced with his teammates Tang Xingqiang, Xie Zhenye and Zhang Peimeng in the heats of the 4 × 100 metre relay.

On 4 August 2017, Su raced in the fourth heat of the first round in the 100 metres subsequently qualifying to the semi-finals by clocking 10.03 seconds.

On 3 March 2018, Su made history by becoming the first male Chinese sprinter to win an individual IAAF World Indoor Championships medal, as he took silver in the 2018 edition's men's 60 metres final.

[11] On 22 June 2018, Su took gold in the men's 100 metres final of the 2018 IAAF World Challenge meet in Madrid with a historic 9.91 seconds; tying the Asian record previously set by Nigerian-born Qatari Femi Ogunode.

[44] Representing team Asia-Pacific, Su capped off his record-breaking year with a silver medal in the 2018 IAAF Continental Cup men's 100 m final.

[46] On 14 February 2019, Su started the year out strong with a 60m victory at the 2019 AIT International Grand Prix, clocking a stadium-record time of 6.52 seconds.

[47] Two days later, Su quickly followed up his good form with a resounding 60m victory at the Birmingham meet of the 2019 IAAF World Indoor Tour.

Running the third leg, Su aided his teammates to a second-place finish in the heats, qualifying them for the final with a time of 38.51 seconds.

[12] Su's 9.83 also placed him among the top 5 fastest men in the history of Olympic 100m races ranking just behind Usain Bolt, Yohan Blake, Justin Gatlin, and Marcel Jacobs.

[52] He and his teammates also qualified for the final of the men's 4×100 m relay and finished fourth in that race in 37.79 seconds, equalling the Chinese national record set in 2019.

[53] On 18 February 2022, Great Britain was stripped of its silver medal in the men's 4×100 m relay after the Court of Arbitration for Sport confirmed CJ Ujah’s doping violation.

[citation needed] On 20 December 2017, Su was elected as one of Zhongshan City's representatives for the 13th People's Congress of Guangdong Province.

[60][61] On 19 September 2015, Su led dozens of school students on Ersha Island to help with fundraising activities for the Chinese charity "Walking for Love".