Having completed his education from King Edward VII High School, Yaseen Valli played his first ever first-class match during the CSA Provincial Three-Day Competition. Batting at number 7 in his debut first-class innings, Valli scored an unbeaten 20 and bowled a handful of overs in the 3-day match against Easterns. He scored few gorgeous boundaries in that drawn match but it was just the beginning of a fruitful career.

Valli has a decent technique and loves to play majority of his shots through the off-side. He has represented teams like Gauteng, Gauteng Under-19s, King Edward VII High School, Lions, South Africa Colts XI, South Africa Under-19s and was recently named in the squad for the Highveld Lions (2018–19). While playing for SA Emerging, Valli scored a century and as a result of his strong performance, the team sealed the one-day series against Zimbabwe A in August 2017. Another interesting fact is that Yaseen Valli and Kagiso Rabada made their first-class debuts in the same match for Gauteng in March 2014.