Eric Jelen was German indoor champion in 1985, 1986, 1987 and German team champion in 1984, 1985, 1986, 1987, 1988. The right-handed took in 1988 at the Olympics in Seoul , where he in the first round in the individual against eventual Olympic champion Miloslav Mečíř retired . Even in doubles, he did not get past the first lap with Carl-Uwe Steeb. On the professional tour in 1989 he won his only solo title in the Bristol singles competition , while he achieved five titles in doubles. His best placement in the individual world rankings was 23rd in July 1986; in the double ranking he finished 18th.
After the end of his career in 1992, Jelen was initially sports director at a sports marketing agency in Essen for many years. He then moved to the sports marketing agency Boris Becker & Co as a freelancer , where he was responsible for tennis. In addition to other consulting activities, he has been a coach and consultant for the Niederrhein Tennis Association since 2010. In 2010 he was part of the organization team for the World Team Cup in Düsseldorf.