maruyama ryuhei was born in kyoto on november 26th, 1983. he, along with yasuda shota, are the only members in kanjani8 that are not from osaka.

maru joined johnny's in 1996, but a fluke in paperwork made him rejoin in 1997 along with fellow kanjani8 members yasuda shota, nishikido ryo, and ohkura tadayoshi. as a junior he was in the group big west, long with yasuda shota and nishikido ryo before being taken out of the group unexpectedly. he was then, later, put in the kansai juniors unit V. West, the kansai counterpart of the tokyo juniors band FiVe and gained popularity as a junior in that unit playing the bass. a little trivia is that he learned guitar first, but due to there being too many people who could play guitar while forming v. west they placed him on bass.

V. West became so popular they hosted their own weekly television show on KTV as well holding their own live before merging with the new group kanjani in 2002 (later becoming kanjani8 in 2003). in late 2004, kanjani8 released their first single, an enka pop tune entitled naniwa iroha bushi as a limited kansai release. the popularity of the song soon marked the group's debut and in 2005, kanjani8 made their nationwide debut. maru's position in the group vocally is harmony and rap, usually singing the same parts as yasu due to their high pitched singing voices. in kanjani8's rock songs, he assumes the role of bassist like he did in v. west.

the debut of kanjani8 skyrocketed maru's career, landing him in dramas and television show apperances. in 2007 until mid 2008 maru was a cohost on the morning ktv show tsuukai everyday, hosting a corner every thursday, he also recieved critical acclaim for his lead in the aichi tv drama special jitensha shounenki, playing an aspiring cyclist alongside his childhood friend and bandmate yasuda shota. he now co-hosts the tv tokyo late night variety ariehen sekai alongside bandmates murakami shingo and yasuda shota as well as a regular on the kanjani8 varieties janiben (kansai tv) and can! jani (tv asahi).

maru's personality is free spirited and wacky, playing the 'idiot' of the group and being the butt of jokes for people's enjoyment. he's known for making one lined gags, his most famous being ' PAAAAAN! '. another popular gag he has is ' I Love You So Much, TO YOU! ' which he usually says with a serious face. he has two younger siblings which he talks highly of a lot and his parents are bodybuilders, his mother a former while his father is still active. he's known for proudly annoucing his love for food and sweets -- something that fellow members yokoyama yuu and nishikido ryo love to pick on him about -- and has a corner in weekly tv guide strictly about which sweet is better than the other. he's known for being very sweet and kind, but also very mysterious.