[4] He debuted as an actor in 2019 in the short film On The Way of the drama anthology Sono Shunkan, Boku wa Nakitaku Natta -Cinema Fighters project-.

He then started to do different part-time jobs, including dish washing at a ramen shop, and spent his wages playing with the pachinko and slot machines in his free time.

Imaichi chose to specialize in pressure welding since the job paid a higher salary than for a normal construction worker.

[6][7][8] Imaichi became a big fan of Atsushi as early as 2000 when he saw him taking part in the Asayan talent search TV show.

When Atsushi debuted as the vocalist of Exile later on, Imaichi quickly became a big fan of the group and learned to sing their songs.

[20][21] In 2013, he sang the national anthem of Japan on the stage of the IBF World Boxing Championship held in Kagawa Prefecture.

On the radio, Imaichi shares the songs and musicians that he loves with his listeners, and he introduced Brian McKnight on his very first broadcast.

[24] In 2015, he released his first solo song "All LOVE" as part of Sandaime J Soul Brothers' album Planet Seven under the name of the group.

[27] In the same year, Imaichi also released his first solo song under his own name titled "Forever Young At Heart" in HiGH & LOW ORIGINAL BEST ALBUM, and the song was used as part of the soundtrack for the TV shows and films of the High & Low franchise, an action and music franchise produced by LDH.

[29][30] On January 12, 2018, while remaining a member of Sandaime J Soul Brothers, Imaichi made his solo debut with the digital single "ONE DAY".

[32] He continued to release more digital singles throughout the year, such as "Angel" on February 16,[33] "Thank you" on March 16 and "Alter Ego" on April 20.

[7] Furthermore, Imaichi released his first photo essay titled TIMELESS TIME on March 26, which was produced by American Artist Daniel Arsham.

[45] On July 1, the live footage of the joint tour, LDH PERFECT YEAR 2020 SPECIAL SHOWCASE RYUJI IMAICHI / HIROOMI TOSAKA, was released and was ranked No.1 on Oricon's weekly DVD, BD and joint DVD/BD ranking at the same time with about 50.547 copies sold in the first week.