Born in Hiroshima in 1987, Kato with his family moved to Osaka soon after and when he was in grade 3 they moved to Tokyo.
Kato Shigeaki joined Johnny's Entertainment on April 17, 1999 at the age of 11. His career was developing fast and soon he appeared on TV shows was allowed to hold a microphone. Kato was put in several temporary units but in Autumn 2001 he together with Koyama Keiichiro became a part of group named J-Support, later renamed K.K.Kity. The group was quite privileged, they backdanced for Kinki Kids and Domoto Koichi even wrote a song for them which they performed at Kinki Kids' Tokyo Dome concert and at TV shows. In January 2003 the three of them became a part of permanent cast of the kids' show called Ya-Ya-yah. In January 2003 the three of them became a part of permanent cast of the kids' show called Ya-Ya-yah.
He officially debuted as a member of a 9-member band NEWS in 2003. However, he soon realized he was one of the least popular members being lost in the shadow of Yamashita and Nishikido. He even considered quitting the band but eventually he decided to concentrate on the things only he could do and bring out his individuality. He started a blog on J-web from the perspective of a fictional cat named Wagahai which was a parody of the popular book by Natsume Soseki entitled "Wagahai wa Neko de Aru" or "I Am a Cat". He got a column in a magazine where he wrote essays on various topics and later when he got really interested in professional photography he also got a page in Wink Up where he could show some of his photographs and write about them.
In 2011 NEWS had almost no activities as a band. Shigeaki was restless. He came to the agency trying to figure out what he could do as Kato Shigeaki and a member of NEWS. In the end it was decided that he should write a novel. He was given a two-month deadline so he shunned himself inside his apartment and wrote. Shige's book came out in early 2012 and was quite a success. Thus Kato Shigeaki became the first man in Johnnys to release a novel. He also decided to change the writing of his name to katakana. Partly so everyone would be able to read it and partly to mark his intent to open a new page on his career and become a better person.
Kato continues to write books while working as a member of NEWS. He also plays guitar, writes music, mostly his solo songs. Shige got to appear in quite a lot of dramas and films having the most acting experience among NEWS members. In 2008 he staged a one-man show "Konnan Yattte Mimashita" which consisted of 20 short stories which he had written himself and since 2009 he also participated in various stage plays. He has his own radio show called "Sorashige book" where he talks about films and music that he likes as well as speaking out about some cultural and social issues.