Windfeder debuted for the senior national team in 2014, in a test series against South Africa. Since his debut, he has been a regular inclusion in the German team. In 2018, he was named in the German team for the Hockey World Cup in Bhubaneswar, India. On 28 May 2021, he was named in the squad for the 2021 EuroHockey Championship and the 2020 Summer Olympics. He scored two goals in the tournament as they won the silver medal after they lost the final to the Netherlands after a shoot-out.