After graduating from the Department of Architecture at Sungkyunkwan University, Lee Minjae began his professional career at Halla Co., Ltd. in 1990. Starting with the expansion site of a cement plant in Okgye, he served as a site representative for various projects including multi-family housing, research facilities, and department stores. At the headquarters, he handled subcontractor selection, administrative affairs, overall domestic site management, quality, safety, and served as the ESG management officer. While working as a manager, he completed the CEO programs (HBS courses) offered by the company and the Korea University Business School. After more than 30 years of service, he retired in 2022 and joined Junglim Architecture as an Executive Director.

At Junglim CM, he has mainly been responsible for PCM, construction period calculation, and field support, and is currently working as Project Director of the Customer Value Technology Center in the Technology Division.