[9] Yoshiki's solo career includes several classical studio albums and collaborations with artists such as George Martin, Bono, will.i.am, St. Vincent, the Chainsmokers, Skrillex, Ellie Goulding, Stan Lee, Roger Taylor and Brian May of Queen, Gene Simmons and KISS, Nicole Scherzinger, and Sarah Brightman.

In 1999, at the request of the Japanese royal family, he composed and performed a classical song at a celebration in honor of the tenth anniversary of Emperor Akihito's enthronement.

Yoshiki was also influenced by works from Led Zeppelin, Iron Maiden, Sex Pistols, David Bowie, Queen, the Beatles, Charged GBH and Pyotr Ilyich Tchaikovsky.

[22] In 1991 they released their hit million-selling album Jealousy, and were the first Japanese metal band to perform in Japan's largest indoor concert venue, the Tokyo Dome.

That same year he began his first solo activities outside X. Collaborating with Tetsuya Komuro for the rock unit V2, with a concert on December 5 at the Tokyo Bay NK Hall[23][24] and the single "Haitoku no Hitomi ~Eyes of Venus~/Virginity" (背徳の瞳〜Eyes of Venus〜) in January 1992, which reached number two on the chart.

[41] Soon afterwards, in May 1998, the band's lead guitarist Hide died, and Yoshiki withdrew from the public scene, as he was battling suicidal thoughts and eventually sought the help of a psychiatrist.

[70][71][72] That same year he co-produced the soundtrack for the 2007 film Catacombs, which included the Violet UK song "Blue Butterfly" and was released by his Extasy Records International.

[110] For an upcoming Japanese 3D CG animated film Saint Seiya: Legend of Sanctuary, Yoshiki contributed theme song "Hero" and it was unveiled on the tour.

[121][122] In 2016, he embarked on another classical world tour, with performances in Tokyo and Osaka,[123] and a Hong Kong show that had to be cancelled due to the promoter's mistake and rescheduled as a free concert on December 30.

[127] However the date was fulfilled on the following day, December 30, by Yoshiki performing for free with ticket holders being refunded, the first time for a major music artist to do such a thing in Hong Kong.

[136] On July 28, 2018, Yoshiki collaborated with Skrillex for performances of "Endless Rain" and "Scary Monsters And Nice Sprites" at Fuji Rock Festival in Niigata, Japan.

[137][138] On October 3, Yoshiki released the song "Red Swan" featuring Hyde, as the opening theme of the third season of the Attack on Titan anime, reaching #1 on the iTunes rock charts in 10 countries.

[151] In November 2019, YouTube Originals announced the documentary series Yoshiki - Life Of A Japanese Rock Star would premiere on the streaming platform in March 2020.

[157][158] In March 2020, Yoshiki collaborated with Bono, Will.i.am, and Jennifer Hudson to create "#SING4LIFE", a song written and compiled remotely by the four musicians to lift spirits during the COVID-19 pandemic.

[161] In November 2020, Yoshiki's photobook XY with images by American photographer Melanie Pullen, placed number one in the Oricon weekly book chart.

[162][163] Yoshiki's online concert presented by YouTube Originals titled Under the Sky, with Marilyn Manson, the Chainsmokers, Nicole Scherzinger, Lindsey Stirling, the Scorpions, Hyde, Sugizo, Sarah Brightman, SixTones, and St. Vincent was postponed from its December 2020 premiere due to post-production delays caused by COVID-19.

[164][165] On December 31, 2020, Yoshiki performed a virtual collaboration of X Japan's song "Endless Rain" on Kouhaku Uta Gassen with Roger Taylor and Brian May of Queen, Sarah Brightman, Babymetal, SixTones, Lisa, and Milet.

Ellie Goulding and St. Vincent joined Yoshiki on stage at Royal Albert Hall as guest vocalists, and the concert was broadcast worldwide by On Air and exclusively in Japan by Wowow.

Through YFA, Yoshiki has supported several charities including the Recording Academy's Musicares foundation, American Red Cross, International Organization for Migration (IOM), Earth Alliance Amazon Forest Fund,[217] Make-A-Wish Foundation, the Australian Red Cross, Rainforest Trust,[218] Japan's National Center for Global Health and Medicine,[224] and St. Vincent Meals on Wheels.

[225] Yoshiki started his charitable work as a result of losing his father to suicide at a young age, saying he wanted to support children who have had traumatic experiences like he did.

[235] In June 2019, Yoshiki visited the Frost School of Music at the University of Miami where he made a $150,000 donation and held a masterclass for students, where he advised the future musicians to "play every concert as if it is your last.

"[236][237] In September 2019, Yoshiki donated 10 million yen to support disaster relief in his hometown of Chiba after it was struck by Typhoon Faxai,[238][239] and later volunteered for manual labor at the recovery site when he returned to Japan.

[240][241] In March 2022, Yoshiki helped raise over US$9 million for humanitarian relief efforts in Ukraine after announcing his own donation to the fundraiser initiated by Hiroshi Mikitani, CEO of Rakuten.

[244][245] In January 2024, Yoshiki donated 10 million yen to the Japanese Red Cross to support areas affected by the Noto Peninsula Earthquake.

[249][250] In December 2019, Yoshiki was named as one of Forbes Asia's 30 Heroes of Philanthropy for his contributions to "disaster relief, orphanages and treatment for children with bone-marrow disease".

[276] In October 2021, French fine crystal manufacturer Baccarat debuted a 180th anniversary version of its Harcourt glass at Paris Fashion Week 2022 designed by Yoshiki.

[277] Yoshiki has launched several business ventures, including music recording, entertainment, wine, energy drinks, fashion, finance, and lifestyle products.

Yoshiki admitted that the clear acrylic shells are great for appearances, allowing the stage lights to color his drums with varying hues, but are not ideal sound-wise.

He explained that the clear drums are difficult to play because they do not have the usual responsiveness of wooden shells and are not very durable; as they require much more physical pounding to deliver a good sound and that causes the heads to be essentially ruined after only a single concert.

[310] However, in the studio he uses a limited made titanium kit from Kitano drum called Tama Artstar II "Titan Body" with Evans coated heads.