Born in
Worms,
West Germany, Kargus began playing football with boyhood club
Wormatia Worms. Having joined the youth ranks of
Hamburger SV in 1970, Kargus stepped up to become a
Bundesliga goalkeeper for the North Germans from 1971, capturing the starting role in the goal of Hamburg in 1973. He served as the club's first-choice until Hamburg headed for a change on that position in 1980. In his years with Hamburg he graduated into a goalkeeper as promising as reliable, known for his ability to save penalties (which earned him the
Elfmetertöter nickname). He won the
European Cup Winners' Cup with Hamburger SV in 1977, was runner-up with them in the
European Cup in 1980 after winning the Bundesliga title the season before. After the end of his deal with Hamburg in 1980 it took him four months to sign a new deal elsewhere, joining
1. FC Nürnberg. He was in the 1. FC Nürnberg team when Nuremberg was relegated to the
2. Bundesliga in 1984, going on for them in the lower division until Bundesliga side
Karlsruher SC snapped him up in December 1984. He had tough luck in this change of clubs since Karlsruher SC could not avoid relegation to the 2. Bundesliga in the remainder of the season and, so, he had to return to playing games on that level in 1985–86. For the campaign of 1986–87 he returned to the Bundesliga with a move to
Fortuna Düsseldorf, but experienced another relegation from Bundesliga with them then. Following Düsseldorf's relegation the then well-travelled goalkeeper signed with another Bundesliga side,
1. FC Köln. However, in his three years with the side from
Cologne he was just the veteran stand-in for Köln's young first-choice
Bodo Illgner and did not manage to get any Bundesliga game for his final professional club. In total, Kargus played in 408 Bundesliga matches in his career and took part 19 times for his clubs in the 2nd Bundesliga. His
West Germany career had started early with youth internationals in his years with
Wormatia Worms. His first senior cap was a product of
Helmut Schön looking for
Sepp Maier replacements and the good form of young Kargus for Hamburg in the Bundesliga. Four days prior to Christmas 1975 Kargus was chosen to represent West Germany in a friendly against
Turkey. He did well and was subsequently named in the
1976 UEFA European Championship squad, serving as (the unused) deputy of
Sepp Maier. A further friendly appearance later, Kargus came on also at half-time against
Yugoslavia in 1977 to replace
Maier. That was the last cap (of three) Kargus won in his career, although he was one of three goalkeepers in the West German squad for the
1978 FIFA World Cup. After the end of his career, Kargus had several stints as coach to school kids in goalkeeping and has been active as artist painter since 1996, painting scenes of football in 2006, but exclusively non-footballing themes after that. He attended an art course at the Kunstschule Blankenese before exhibiting his paintings. ==Honours==