Filip Šnejdr gained his first international experience in 2017 when he finished fifth at the U23 European Championships in Bydgoszcz over 800 meters in 1: 49.19 minutes. He then reached seventh place at the Summer Universiade in Taipei over 800 meters in 1: 48.31 min and won the bronze medal behind the teams from the Czech 4 x 400 meter relay in 3: 08.14 min Dominican Republic and the United States. The following year he finished fifth at the World Indoor Championships in Birmingham with the relay in 3: 04.87 min. He also qualified for the European Championships in Berlin , where he retired over 800 meters with 1: 48.70 min in the first round and took seventh place in the relay in 3: 03.00 min. In 2019 he reached the European Indoor Championships in Glasgow and reached the semi-finals there, in which he was eliminated with 1: 50.72 minutes. He then finished fourth over 800 meters at the Student World Games in Naples in 1: 48.08 min and reached fifth place in the relay in 3: 06.78 min.
In 2017 and 2019, Šnejdr became the Czech champion in the 800-meter run outdoors. In the hall, he secured the title in 2016, 2017 and 2019. In 2017, he was also the indoor champion in the 4 x 200 meter relay.