Stal was born in Décines, near Lyon.[2] He played on the Challenge Tour in 2012. He won his first title in June 2012 at the Kärnten Golf Open, playing on an invitation.[3] The following month, Stal picked up another victory at the Credit Suisse Challenge, defeating Alexandre Kaleka in a playoff and graduated to the European Tour.[4] He was less successful in 2013, but performed well at the second and final stages of Qualifying School to regain his place on Tour.[5] He then finished 89th on the 2014 Order of Merit, making 21 cuts in 25 tournaments.[6]
On 18 January 2015, Stal secured his first victory on a major tour, shooting a −7 in the final round to win the European Tour's Abu Dhabi HSBC Golf Championship by one stroke over Rory McIlroy.[7]