Marcus Alstrup

Marcus Alstrup came through the Odense BK academy, and in 2020 he was part of the side that won the Danish youth championship with the club's under-19 team. Two years later he left for Sønderjyske, where he made his first-team debut in November 2022.

A short spell followed at B.93 in the Danish second tier, where he made two appearances for the first team before, in 2024, moving abroad to Austin FC II in MLS NEXT Pro. He spent two seasons with the club, making 28 appearances there.

In July 2026, Alstrup signed for San Diego FC as a free agent, on a deal running through the end of the 2026 season with options for 2027. The move went through a supplemental roster spot rather than any significant transfer fee. He has yet to appear for the first team in MLS or the Leagues Cup; he did not score away, but conceded ten goals and kept one clean sheet.

Alstrup has represented Denmark at under-15, under-17 and under-18 level, making nine appearances across the youth national teams, but has not been called up to the senior side.