Shimada was born in the United States and started his professional career in 1993. He specialized in doubles early on and won a total of seven doubles titles on the second-rate Challenger Tour in his career. He also achieved three tournament victories on the ATP Tour and three other finals. His highest ranking on the doubles world rankings was position 40 in 2004. In doubles competition, his best result at a Grand Slam tournament was always the second round he was able to achieve in all Grand Slams.
Shimada played between 1994 and 2003 in a total of 16 matches for the Japanese Davis Cup team . He was always used in doubles, although his partners varied. Seven wins face nine defeats.