After finishing his active career, Jareš started to work as a football manager. He coached Slavia Prague in two separate stints, once in 1973-1979 and again in 1984–1986. Under his management, Slavia ended up third in the Czechoslovak League on four occasions. From 1987-1990 he coached Dukla Prague and finished second in the league in the 1987–1988 season.