JLOC (2014-2018)

After spending most of 2014 out of racing, Hiramine made his Super GT debut in the 2014 Suzuka 1000km, as a third driver for JLOC in their number 88 Lamborghini Gallardo GT3. He finished 13th in his series debut.

He became a full-time GT300 driver beginning in 2015, partnering two-time series champion Manabu Orido in JLOC's flagship number 88 team. In six races, Hiramine recorded two fourth-place finishes at the Suzuka 1000km and at Sportsland Sugo. JLOC switched to the new Lamborghini Huracán GT3 in 2016. Hiramine recorded his first GT300 podium at Motegi, when he and Orido finished third in the first race of a double-header weekend. He and co-driver Orido finished 11th in the championship. Hiramine returned to partner Orido for the 2017 season. He recorded a career-best finish of second in the final Suzuka 1000km. Hiramine and Orido finished tenth in the championship.

The following year, Lamborghini works driver Marco Mapelli replaced Orido in the number 88 Lamborghini. Mapelli won the pole for the opening round at Okayama, and Hiramine won his first pole at the season finale at Motegi. Hiramine recorded six straight top-ten finishes to open the season, and finished tenth in the drivers' championship.

While at JLOC, he also entered the Lamborghini Super Trofeo Asia series on a part-time basis, and won the Pro-Am class in race one of the 2015 round at Sepang Circuit. In 2016, he made his Intercontinental GT Challenge debut with JLOC, competing in the Sepang 12 Hours. He finished eighth overall. In 2018, he entered the inaugural Suzuka 10 Hours with JLOC, partnering Mapelli and fellow Lamborghini factory driver Andrea Caldarelli in a Pro class car sponsored by EVA Racing (Run'A Entertainment).

Kondo Racing (2019)

While competing for JLOC in Super GT, Hiramine returned to Super Taikyu, competing full-time in the premier ST-X (GT3) class with Kondo Racing and Nissan Automobile Technical College in their Nissan GT-R NISMO GT3. He helped Kondo Racing win the 2016 championship with four wins in six races, and finished runner-up in 2017 and 2018.

In 2019, Kondo Racing's ST-X team moved up to the GT300 class of Super GT, and Hiramine left JLOC to continue with Kondo Racing, with former Renault Sport Academy member Sacha Fenestraz as his team mate. Driving the newest generation of the Nissan GT-R NISMO GT3, Kondo Racing had a successful first GT300 campaign. Hiramine won the pole for the Fuji 500km race on Golden Week, and in the fourth round at Chang International Circuit, Hiramine and Fenestraz were leading the GT300 class until the final lap, when Hiramine was overtaken by the #10 Gainer Nissan of Keishi Ishikawa (with co-driver Kazuki Hoshino), and dropped to second. With seven top-ten finishes, Hiramine and Fenestraz finished sixth in the GT300 standings.

Hiramine was meant to take part in the 2020 Nürburgring 24 Hour Race with Kondo Racing, but their entry was cancelled due to the COVID-19 pandemic.^[4]

Team Impul (2020-present)

Hiramine was invited to take part in a post-season GT500 test for Nissan at Fuji, following the conclusion of the 2019 season.^[5] On 10 January, Hiramine was officially announced as a Nissan GT500 driver, joining Team Impul as a driver of the number 12 Calsonic Impul Nissan GT-R.

In his first GT500 season, Hiramine was partnered by Daiki Sasaki. While they struggled early in the season, Hiramine did capture his first GT500 podium by finishing second in the sixth round of the championship at Suzuka. In 2021, Sasaki moved to Kondo Racing, and Nobuharu Matsushita, the former GP2 Series/FIA Formula 2 driver, made his GT500 debut with Nissan and Team Impul. Hiramine and Matsushita won in GT500 for the first time at Sportsland Sugo. At the penultimate round at Motegi, Hiramine was leading on the final lap, but ran out of fuel and dropped to third place. A win would have moved Hiramine and Matsushita to within eight points of championship leader Naoki Yamamoto. Instead, they fell to sixth in the championship heading into the final round at Fuji. They would finish the year eighth in the final standings, with two podiums and seven top-ten finishes.

Before the 2022 season, Matsushita and Bertrand Baguette swapped manufacturers and teams, with Baguette joining Nissan and Impul after eight seasons as a Honda driver. 2022 also saw the debut of the new Nissan Z GT500 race car, which replaced the GT-R as the company's flagship GT500 vehicle. The new combination of Hiramine and Baguette finished third in a shortened Fuji 450km race on Golden Week. Two months later, they finished second at the Fuji 100 Lap Race. At the Suzuka 450km race, the Calsonic Z qualified 15th and last in class, but came back to win the race as Hiramine took the lead with three laps to go.^[6] The Calsonic Z finished fifth at Sugo, sixth at Autopolis, and in the final race at Motegi, Hiramine, Baguette, and Team Impul clinched the GT500 Drivers' and Teams' Championships with a second-place finish. This was the first set of Super GT titles for Team Impul since the 1995 season, and the first GT500 titles for Hiramine and Baguette.^[7]