He played as left-back and became one of the main player in a successful era of the club.
After working as a TV pundit, Soma managed the Japan Football League side FC Machida Zelvia in 2010.
He held a managerial post in charge of J1 League side Kawasaki Frontale prior to the 2011 season.
On April 12, 2012, Kawasaki dismiss coach Naoki Soma after performing 'far below expectations'.
The 40-year-old coach was sacked with the club's president stating the team were performing 'far below expectations' having aimed to win the title this term.
On 14 November 2024, Soma announcement officially appointment manager of Kagoshima United from 2025.