Yamamoto's interest in working in the anime industry piqued in high school after realizing how noticeable the difference in episodes were depending on the episode director in charge. One of his favourites shows included anilist.co/anime/929.
In the late '80s, he joined Sunrise as a production assistant after finding out that it's how many of the studio's directors started off. There he met and studied under Shuuji Iuchi on his shows anilist.co/anime/2818 and anilist.co/anime/4807. Then after having gone freelance he got his first shot as a director as one of the three unit directors on Iuchi's anilist.co/anime/418 in 1991.
In 2001, Yamamoto made his debut as a series director on anilist.co/anime/2934, soon after which he worked as the first director of the long-running anilist.co/anime/516. In 2006 he directed the well-received anilist.co/anime/1210
More recent directorial works of his include anilist.co/anime/14355 and anilist.co/anime/21321.