Aya Kyogoku joined Nintendo in the early 2000s, initially working as a game designer. Specific details about her earliest projects are scarce, but this period was crucial for honing her skills and understanding Nintendo's design philosophy, laying the foundation for her future leadership roles. This initial phase likely involved contributing to various projects and learning from experienced developers.

Kyogoku was a game designer for "The Legend of Zelda: Four Swords Adventures" on the GameCube. This marked her involvement in a major Nintendo franchise and provided valuable experience in working within a larger team on a complex project. It also exposed her to the challenges and rewards of contributing to a beloved and established series.

Kyogoku took on the role of scriptwriter and designer for "Animal Crossing: Wild World" on the Nintendo DS. This was a pivotal moment as she began to significantly influence the direction of the "Animal Crossing" series. Her work on the script and design helped shape the game's charming and engaging world, contributing to its massive success and establishing her as a key figure in the franchise's development.

Aya Kyogoku stepped into the director role for "Animal Crossing: City Folk" on the Wii. This promotion demonstrated Nintendo's confidence in her abilities and marked her as a leader within the "Animal Crossing" team. As director, she oversaw the entire development process, guiding the team's creative vision and ensuring the game's quality.

"Animal Crossing: New Leaf" on the Nintendo 3DS was another critically acclaimed entry in the series that Kyogoku directed. The game introduced significant new features, such as becoming the mayor of the town, further expanding the gameplay possibilities and solidifying the franchise's popularity. Her direction ensured that these new elements were seamlessly integrated into the established "Animal Crossing" formula, appealing to both long-time fans and newcomers.

Kyogoku was promoted to Manager of Production Group No. 5, and became a producer for "Splatoon" on the Wii U. This move was significant as it expanded her responsibilities beyond the "Animal Crossing" series and into a completely new IP. As a producer, she oversaw the development and ensured the success of "Splatoon", a game that quickly became a major hit for Nintendo. Her involvement in "Splatoon" demonstrated her versatility and ability to manage a different type of game effectively, leveraging experience from past game development. This expanded responsibilities from director to producer, including leadership duties.

While still involved with "Splatoon 2", Kyogoku also served as a producer for "Animal Crossing: Pocket Camp" on mobile platforms. This marked the "Animal Crossing" series' entry into the mobile gaming market. Her oversight as producer ensured that the mobile adaptation retained the core charm and appeal of the main series while adapting to the unique demands of mobile gameplay.

Kyogoku returned as producer for "Splatoon 2" on the Nintendo Switch, further solidifying her role in shaping the "Splatoon" franchise. The game built upon the success of its predecessor, introducing new features, maps, and weapons, and benefiting from Kyogoku's continued guidance and oversight to be critically acclaimed.

Kyogoku served as a producer for "Animal Crossing: New Horizons" on the Nintendo Switch. This title became a global phenomenon, particularly during the COVID-19 pandemic, offering players a comforting and engaging escape. Her role as producer was crucial in ensuring the game's polish, depth, and widespread appeal, making it one of the best-selling games on the Nintendo Switch and a cultural touchstone.