This study examines how Kakao has been able to successfully build a new type of business ecosystem and expand its services through related literature reviews and interviews with officials. Kakao provides financial and non-financial systematic investment and support from the start-up period to the growth period of start-ups through its subsidiaries. For the growth of start-ups, Kakao helps in various practical aspects such as improving their organizational culture using its human capabilities, providing solutions using information technology capabilities, providing effective distribution channels for content, developing content incorporating its existing assets, and supporting to prevent hacking that may occur in applications, allowing start-ups to successfully develop and market services for customers. Kakao’s case of successfully forming a business ecosystem through support for start-ups, collaboration with them, and service expansion based on customers’ needs can give a successful precedent for companies to create a business ecosystem through collaboration with start-ups.