[3] During the Summer Koshien tournaments, he pitched two consecutive complete shutout games in both the semi-finals and finals (only surrendering two hits in each game), recorded the fastest pitch of 153 km/h (95 mph) and tied the tournament record for the most strike-outs in the finals match (14).

[6] In the fall, he again pitched for the national team in the 25th 18U(AAA) Baseball World Championship where he recorded a 1.11 ERA in over 24 innings, and got selected into the tournament's Best Nine.

[7] In addition, he received the 2012 MVP Award by the International Baseball Federation (IBAF) under the 18 & below category for his exemplary performance for the year.

[8] Fujinami was the number 1 pick of the Tigers, Buffaloes, Marines, and the Swallows in the 2012 Nippon Professional Baseball draft.

He made his debut on March 31, 2013, the third game of the season and the earliest-ever appearance by a rookie drafted out of high school.

[9] He was due to make his second start on April 7 against the Hiroshima Toyo Carp but was replaced by Minoru Iwata who was unable to pitch in the rained-out game the day before.

[10][11] He made his second start on April 14 against the Yokohama DeNA BayStars and recorded his first professional win, pitching six scoreless innings.

[18] Fujinami pitched his first career complete game in a July 15 contest against the Dragons with a 13-strikeout effort and only a single run allowed.

On December 1, 2022, the Tigers posted Fujinami to Major League Baseball (MLB), giving clubs 30 days to negotiate with him, and necessitating a compensatory fee if a deal was reached.

[26][27] He allowed a seventh-inning leadoff first-pitch homer to José Siri in his one frame out of the bullpen in his Orioles debut in a 3–0 loss to the Tampa Bay Rays at Tropicana Field two nights later on July 21.

[28] He pitched a perfect tenth inning to earn his first MLB save in a 5–3 win over the Seattle Mariners at T-Mobile Park on August 13.

[29] He would earn his second career save against the Angels on September 5, inducing a fly ball and striking out two batters in the tenth inning of a 5-4 Orioles win.