Uchitomi established himself at national level in 1993 when he won the 1500 metres title at the Japanese National Games. He had his first successes in the 3000 metres steeplechase during the 1994 track season. He set a personal best of 8:33.04 minutes at the Japan Championships in Athletics, then went on to take his first major medal at the 1994 Asian Games, held in Hiroshima. He won the national title in the steeplechase for the first time in 1995. He retained that title the following year with a personal best run of 8:30.16 minutes and also took the Japanese Games title in the event that year.