They defeated Niigata Prefectural Shibata Agricultural High School, whose battery consisted of right-hander Kazuhiro Togashi (who later played for the Hokkaido Nippon-Ham Fighters) and catcher Ken Katoh, in their first game.

Though Wada, who was not only the team's ace but also their cleanup hitter, gave up a home run to Hichori Morimoto, Hamada High won 3–2, making it to the quarter-finals.

As a player who was born in the 1980 Japanese academic year and participated in the 1998 Summer Championship, Wada is considered a member of the "Matsuzaka Generation".

He rebuilt his pitching mechanics from scratch that year, succeeding in increasing the velocity of his fastball until it consistently hit speeds of 140 km/h (87 mph) and above within a mere two months of joining the team.

Taking on the uniform number 18 that had traditionally denoted the team's lefty ace (previously worn by Shugo Fujii), Wada led Waseda to consecutive Tokyo Big6 league titles in the spring and summer seasons of his senior year (2002) for the first time in university history since 1950.

His dedication and commitment were said to have had a positive influence on younger players on the team like Norichika Aoki, Takashi Toritani, Toshimitsu Higa and Shintaro Yoshida (all of whom later went pro), the core that later led Waseda to four consecutive league titles for the first time in Tokyo Big6 history.

He was signed by the Fukuoka Daiei Hawks as a pre-draft pick along with right-handermdy Nagisa Arakaki of Kyushu Kyoritsu University prior to the 2002 NPB amateur draft that fall[3] and was assigned the uniform number 21.

Wada secured a spot in the Hawks' starting rotation from his rookie year (2003), making his professional debut in a regular season game against the Osaka Kintetsu Buffaloes on April 1 (he gave up five runs in 6+2⁄3 innings).

Overall, he finished the year with a 14–5 record,[4] 3.38 ERA and 195 strikeouts (second only to young Lions right-hander Daisuke Matsuzaka's 215), earning Pacific League Most Valuable Rookie honors.

However, he fell victim to a so-called sophomore slump in the regular season, going 10–6 but racking up a 4.35 ERA and striking out just 115 batters (despite this, his batting average against was a league-best .228).

In 2005, Wada was named the starter for the Hawks' season opener for the first time in his career, taking the mound against the Fighters on March 26 and holding them to one run over 7+2⁄3 innings while striking out eight en route to the win (though he required 135 pitches).

On December 10, the Fukuoka SoftBank Hawks made it public that Wada had married swimsuit model and actress Kasumi Nakane.

[10] He pitched the most innings (182) and amassed the most strikeouts (169) since his rookie campaign and became the only active pitcher other than the aforementioned Masanori Ishikawa (and the first in Hawks franchise history since Sugiura) to record double-digit wins in each of the first five seasons of his professional career.

Despite the slight setback, he started the season of well, putting up eight wins before the All-Star break and garnering selection to the Japanese national team that would play in the 2008 Beijing Olympics.

However, he did not pitch as had hoped in the Olympics,[11] giving up six runs (five earned) in two starts en route to a 4.82 ERA over 91⁄3 innings (albeit while striking out 13) and being one of the factors in Japan's disappointing fourth-place finish[12] behind South Korea, Cuba and the United States.

While he pitched reliably, recording a 3.18 ERA in his final six starts of the season, he was victimized by a lack of run support and failed to put up double-digit wins for the first time in his professional career.

In 2009, Wada was named to the national team's preliminary roster for the upcoming World Baseball Classic[13] along with teammates first baseman Nobuhiko Matsunaka, starter Toshiya Sugiuchi, closer Takahiro Mahara and shortstop Munenori Kawasaki.

[14] Wada showed no signs of disappointment in his pitching, taking the mound in the Hawks' season opener on April 3 and striking out 14 (tying both his career high and the NPB record for strikeouts in a season opener) en route to a three-hit, complete game shutout against the Buffaloes[15][16] in one of the most dominant starts of his young career.

His third start was one of the best in his career, as he gave up one run on four hits in a complete-game effort, striking out a career-high 15 Marines to record his second win of the season.

[17] Wada underwent Tommy John surgery on May 11, 2012 due to a partially torn ligament in his left elbow and spent the rest of the 2012 season on the disabled list.

He was back pitching as a reliever toward the end of the regular season before suffering a left leg injury that ruled him out of postseason action.

[37] He compensates for this with his deceptive arm swing and late release point,[38] complementing it with a solid-average slider, an occasional curveball, and a changeup.

However, he has shown marked improvement in this area since making his professional debut, giving up progressively fewer homers in every season of his career except for 2005.