Hiemer played his junior hockey at the same time as NHL veteran Uwe Krupp. Hiemer, two years older, was considered to be a better player at that time. Hiemer was drafted 48th overall by the Colorado Rockies in 1981 while the gigantic Krupp was drafted 223rd overall in 1983.
Hiemer joined the relocated Rockies in New Jersey in 1984 after representing Germany in the Canada Cup tournament. He played in 53 games scoring 5 goals and 29 assists. Three of his goals came against Pittsburgh on Hallowe'en 1984, establishing a franchise record for goals by a defenseman in one game.
Hiemer would struggle along with the rest of the Devils the next two seasons. He played another 90 games but also saw time in the American Hockey League. He became the first German-born player to play regularly in NHL history, but after three years was still having problems adjusting to the more rugged North American style of game.
"Hiemer had a lot of trouble adjusting," recalls his head coach, Doug Carpenter. "European teams don't play as often as we do, and the traveling just doesn't compare. The hockey is played at a different pace, too. All in all, it's quite a shock."
"So what I did," continued Carpenter, "was let Hiemer get his feet wet on our power play. He's good at that, see. And so he gradually got the idea that he could carry the puck and pass it effectively in this league. With that confidence, he was able to take on more and more work."
Hiemer returned to Germany in 1987. In 143 NHL games he scored 19 times and had 73 points. 11 of his 19 goals came on the power play.
In addition to his NHL experience, Hiemer represented Germany in three Olympic tournaments, nine World Championships and one Canada Cup tournament in his 14 years of service with the German national team. He also was a standout with Dusseldorfer upon his return to Germany, scoring over 200 goals in his career in the German leagues.