After graduating from university, Yamaguchi started out being in charge of a company that sold teaching materials. Yamaguchi started working at Loftwork in December 2004 and, having been appointed the creative director, he started out by working on sites that use CMS, and then later on took on a supervisory role for various projects, including development for Web related applications that employ new technology. In October 2007, Yamaguchi took charge of Loftwork's marketing department, and is currently handling all things management for loftwork.jp. Being a fan of cameras, laptops and other high-tech devices, Yamaguchi is already surrounded by countless gadgets when he works. In September 2013, he received his Google Analytics Individual Qualification (GAIQ).