His Amateur Championship win gave an entry to the 2015 Open Championship where he made the cut and finished tied for 65th place.[3] He also got an entry to the 2016 Masters Tournament where he was one of two amateurs to make the cut and finished tied for 39th place.
Langasque started the 2017 European Tour season by finishing tied for tenth place in the Australian PGA Championship. This was his only top-10 finish of the season and he finished 151st in the Race to Dubai, losing his European Tour place.
In December 2017 he finished tied third at the AfrAsia Bank Mauritius Open, where he had been invited. He then missed the cut in 5 of the 6 other European Tour events he was able to play, the last of them being the HNA Open de France in July 2018. Back on the 2018 Challenge Tour, he had a difficult start, earning less than €6,000 until mid-July. From the Le Vaudreuil Golf Challenge he started playing more solidly, making eight cuts in a row, including a tied fifth place at the Kazakhstan Open in September and his first professional victory a week later at the Hopps Open de Provence. Despite a fourth-place finish in the Ras Al Khaimah Challenge Tour Grand Final, he finished 19th in the Road to Ras Al Khaimah rankings, missing out on a European Tour place. However, less than two weeks later he finished in fifth place in the European Tour Q-School to earn a place on the European Tour for 2019.
Langasque had a successful start to the 2019 European Tour season, finishing second in the South African Open in December 2018. The event was part of the Open Qualifying Series and his high finish gave him an entry to the 2019 Open Championship, his first major as a professional. He had solo third-place finishes in the Made in Denmark tournament and the Scottish Open and finished the 2019 season 24th in the Order of Merit.
On 23 August 2020, Langasque won the ISPS Handa Wales Open by two shots over Sami Välimäki. He shot a final round 65 to overturn a five-shot deficit for his first European Tour win[6] and advanced to 100th on the Official World Golf Ranking, tying his career best ranking from July 2019.