Kenteris specialised in the 200 m and 400 m. His first national titles were the three consecutive 400 m gold medals at the Greek Athletics Championships (1991 (46.90), 1992 (46.85), 1993 (46.27)) in Athens with 200 m (21.57) and 400 m (47.76) gold medals at the 1993 Greek Indoor Athletics Championships in Piraeus, representing his home town team, Arion Mytilene. He also competed at the 1992 World Junior Championships in Seoul where he finished 6th in 200 m (21.10). His first major international title was the gold medal in 400 m (45.70) at the 1993 Mediterranean Games in Narbonne. At the 1994 Greek Indoor Athletics Championships in Piraeus, he defended his 200 m (20.93) and 400 m (46.73) gold medals. He repeated his success in the 400 m (47.11) by winning gold at the 1996 Greek Indoor Athletics Championships. In 1997, Kenteris moved to Athens and Olympiacos CFP, with whom he won the 4 × 100 m relay gold (40.86) at the 1997 Greek Athletics Championships in Athens. Kenteris repeated his success the following year when he won the 400 m (45.87) and 4 × 400 m relay (3:11.95) gold medals at the 1998 Greek Athletics Championships in Athens.