Pozzi begun his career competing for Stratford AC, of which he is still a first-claim member. From 2010-11 he competed as a junior for 'Avon Spa', a joint effort between and in the . Pozzi currently holds the record for the fastest ever time run by a UK junior hurdler, setting the record at the Bauhaus Junior Gala in Manheim, Germany on 3 July 2011. He won a Silver medal at the 2011 European Junior Athletics Championships in Tallinn, Estonia with a time of 13.57s and immediately began focusing on making the transition from junior events to senior competitions. He ended his junior career on a high, beating his senior rivals in the 110m hurdles to win the McCain UK Challenge Senior Final with a time of 13.84 – his second fastest wind-legal clocking over the senior hurdles, made all the more impressive given the -1.0 m/s headwind.
Senior career
Pozzi started life as a senior athlete well, winning his first 7 races and clocking a new personal best of 7.62 over 60m hurdles at the Birmingham Games. He went on to be crowned UK Indoor Champion on 12 February after winning at the Aviva European Indoor Trials & UK Championships in Sheffield, once again equalling his personal best. On 18 February he competed at the Aviva Grand Prix against Olympic Gold medalist and World Champion Liu Xiang, and World Indoor Champion Dayron Robles. Pozzi performed well, finishing 7th in the final after automatically qualifying by coming 3rd in his heat with a time of 7.62. Pozzi was selected to represent Great Britain at the 2012 World Indoor Championships in Istanbul, his first senior International representation. He was the only British male sprint hurdler selected. He surpassed expectations by winning his heat, beating Liu Xiang in the process, with a new personal best of 7.61s which also made him fastest qualifier. Pozzi continued to impress by finishing second in the semi-finals with another personal best of 7.56s making him the second fastest British 19-year-old ever, just 0.01s behind Colin Jackson's record. He finished 4th in the final with a time of 7.58s. On 7 May 2012, Pozzi won gold at the BUCS championships at the Olympic Stadium, London. In the heats he achieved the Olympic "A" qualifying standard time of 13.52s. It was his first outdoor race of the season. He went on to win in the final with an even better time of 13.35s, making him the fastest European 19-year-old over 110m hurdles of all time.
Pozzi was selected to compete for Team GB after winning the British Olympic Trials on 24 June 2012. Whilst competing at a Diamond League event in Crystal Palace on 13 July 2012 he became injured in the final but was set to recover in time for the Olympic games. By the date of his race on 7 August it was reported that Pozzi was not fully fit but would compete. After clearing the first hurdle it became clear that he had not recovered and immediately clutched his hamstring. He later said "The last month has been a nightmare. I haven’t been able to get my hamstring sorted. Being in the Olympics is all I’ve been waiting and training so hard for. To leave like that is heart‑breaking."
Birmingham 2018 World Indoor Athletic Championship
Pozzi qualified for finals with a terrific run in both heats and semi-finals. In the finals, he edged Jarret Eaton of the USA by just one-hundredth of a second to clinch the gold medal with a time of 7.46 sec.
