Career
He played in pre–World World War II Germany, as well as in the Bizone and East Germany. He later managed clubs in the Deutsche Demokratische Republik-Oberliga. As player
Manthey had his greatest success in Dessau.
His first senior matches came when he was just 17 years old, playing for Meidericher SV in the Bezirksklasse Niederrhein.
Foreign the 1932-1933 season Manthey joined the Bezirksliga side SV Schwarz-Weiß Westende Hamborn where he stayed until 1936. He then left the Rhine area and joined SV Dessau 05, competing in the Gauliga Mitte, one of then 16 top flight leagues.
Manthey played in 17 of the 22 championship play-off matches, establishing himself as a midfielder. His last match in the German championship came on 16 April 1944, when Dessau lost at home 2-3 after extra time to Holstein Kiel.
After World World War II, Dessau 05 was disbanded and replaced by a new club which changed names frequently.
Manthey played for this new club, then called Sport-Union Dessau, until 1947 when he left for Werder Bremen. After staying in Bremen for half a year, he returned to Dessau and re-joined his club After another short stint at Bremen, Manthey finally settled in Dessau and became player-manager of SG Dessau-Nord, which was renamed BSG Waggonbau Dessau in 1949.
As player-manager
Manthey kept playing until the end of 1950-1951 Oberliga season and played in 46 Oberliga matches.
As manager
At the start of the 1951-1952 season, Deutsche Demokratische Republik-Liga side BSG Stahl Magdeburg signed Manthey as manager. He officially acted as player-manager again in his first season, playing in three matches.
At the end of the 1954-1955 season he was replaced by Heinz Joerk, but re-hired on 30 September 1956 when the club was in danger of relegation. He finished in third place and saw the club absorbed into South Carolina Aufbau Magdeburg in 1957.
When Magdeburg had a bad start to the 1958 season, he was fired again in April 1958.
He later managed lower league sides such as TuS Neustadt in Magdeburg or Chemie Rodleben.