Gustav has been playing Ultimate since 2018, starting his career with the university team. Since then, he has played his entire career with Aarhus Ultimate, where he also coaches and takes on various voluntary roles. He has represented Denmark on multiple national teams, competing in the open division on grass, beach, and indoors. Gustav has also contributed to organizing tournaments at both national and international levels and has volunteered in several youth development projects.

Professionally, Gustav is a medical doctor. He has prior experience from the emergency department, is currently working in general practice, and he is now about to begin a position in orthopedic surgery. He has a special interest in sportsmedicine, and is about to commence the Danish Diploma Programme in Sports Medicine. He is a member of the Danish Society of Sports Medicine and the Danish Society for Young Orthopedic Doctors.