Itagaki joined Tecmo in 1992 as a graphics programmer, and initially worked on the Super Famicom version of the American football video game, "Super Tecmo Bowl". His career breakthrough came in 1996 with his first "Dead or Alive" game, a game based on Sega Model 2 hardware ("Virtua Fighter") created in response to Tecmo management's request. He was mentored by Yoshiaki Inose (of "Solomon's Key", "Bomb Jack", "Rygar" and original "Ninja Gaiden" fame) and Akihiko Shimoji ("Tecmo Bowl") in his early years at Tecmo, and was impressed by them to include fun as a necessary component in his projects.