Klaus Jacob was a member of the East German coxed fours silver medal crew at the 1968 Mexico Olympics. In his early years, he rowed in the coxless pairs with Manfred Gelpke, winning the national title in 1966. Both then moved into the eights, and won the national title in 1968.
The eights were then split into a coxed fours and coxless fours for the 1968 Olympics, with Gelpke and Jacob rowing with the coxed four. This crew won the East German title in 1969. Jacob later studied motor vehicles, agricultural and conveyor technology in Dresden.