Sakagami was influenced to join the theatre group Gekidan Wakakusa at the age of three due to the death of his grandmother.

[1] He was enrolled by his parents in hopes of making friends,[2] but instead flourished in acting and quickly rose to prominence in the industry.

At the age of four, Sakagami starred in several television dramas and variety programs, and was called a "child prodigy" with his natural acting skills.

[3] He continued acting as his main career path into his teens, when Sakagami's father went into bankruptcy and accumulating a large sum of debt from his addiction to gambling.

[10][11] From then on, he became a prevalent figure and television personality in the entertainment industry, with hundreds of program appearances per year.