Astrup joined the Denmark winning team at the 2016 Thomas Cup in Kunshan, China, where he and his teammates beating Indonesia 3–2 in the final.

In 2016, Astrup joined the Denmark winning team at the 2016 Thomas Cup in Kunshan, China, where he and his teammates beating Indonesia 3–2 in the final.

In the final, Astrup and Anders Skaarup Rasmussen received an easy win to their compatriot Mads Conrad-Petersen and Mads Pieler Kolding, after Kolding had to withdraw due to abdominal injury before going into the second game.

[4] In September, Astrup and Rasmussen claimed their first ever BWF World Tour Super 1000 title in the China Open after beating host pair Han Chengkai and Zhou Haodong in the final.

[8] Astrup competed at the 2019 European Games, and won the silver medal in the men's doubles with Anders Skaarup Rasmussen.

[17] Astrup competed at the 2020 Summer Olympics in the men's doubles partnering Anders Skaarup Rasmussen.

[19] The duo were defeated in the semi-finals by the Chinese pair He Jiting and Tan Qiang,[20] In 2023, Astrup managed to win the gold medal at the European Games with his partner Rasmussen.

[5] At the BWF World Championships, he and his partner then upgraded the bronze to silver that they won in 2021, after battling the final match in Royal Arena against the rising Korean pair Kang Min-hyuk and Seo Seung-jae which ended in defeat in a close rubber game.