He played school rugby for HTS Middelburg in Mpumalanga, which led to his inclusion in the Pumas U18 squads that played at the Craven Week competitions in 2010 and 2011.
He was selected in the South Africa U20 side that played at the 2013 IRB Junior World Championship in France. His only appearance in the pool stages came when he came played off the bench in the 97–0 victory over the United States.[3] He didn't play in their matches against England[4] and France,[5] but he did return to the bench for their semi-final clash with Wales. He came on in the first half and scored one of South Africa's two tries in the match, but it wasn't enough to prevent them losing the match 18–17 as Wales progressed to the final.[6] Smith was again named in their final match of the tournament, the third place play-off against New Zealand, and once again scored a try for the Baby Boks to help the team to a 41–34 victory, clinching third place in the competition.[7]
He was selected in the squad that played at the 2014 Commonwealth Games and helped his side to a 17–12 victory over a New Zealand team that won the previous four consecutive tournaments.[9]
Smith was included in a 12-man squad for the 2016 Summer Olympics in Rio de Janeiro.[11] He was named in the starting line-up for their first match in Group B of the competition against Spain, with South Africa winning the match 24–0.[12][13]
Smith was named in the South Africa squad for the 2019 Rugby World Cup.[15] Smith played two matches, against Namibia and Canada in the pool stage, starting both at openside flanker. South Africa went on to win the tournament, defeating England in the final.[16]
In 2021, Smith was part of the South Africa squad for the tests against the British and Irish Lions and Georgia. In the game against Georgia, he scored his first test try, playing as 8th man. He went on to feature for the rest of 2021, including the 2021 Rugby Championship and 2021 Autumn Nations Series, predominantly at the blindside flank and also number 8.
