This study examines Align Partners’ activist engagement with SM Entertainment (SM), from its shareholder proposal to the control contest. Although SM was a leading company in the K-pop industry, persistent concerns had been raised about its dependence on its founder and controlling shareholder, Lee Soo-man, including its contract with his private company and limited board independence. In 2022, Align Partners called for governance reform through a shareholder proposal to appoint an auditor. Its campaign for firm-value enhancement gained support from minority shareholders, prompting SM to accept its proposals. In 2023, SM’s third-party allotment of new shares and issuance of convertible bonds to Kakao escalated the dispute into a contest for corporate control. Lee Soo-man sought an injunction against the issuance and agreed to sell his shares to HYBE. The ensuing contest for corporate control involved two competing groups: SM, Kakao, and Align Partners, and HYBE and Lee Soo-man. HYBE’s tender offer fell short, whereas Kakao’s subsequent offer succeeded, enabling it to prevail in the control contest. Align Partners’ role thus extended beyond governance advocacy to the contest for corporate control. This study demonstrates how shareholder activism initiated through a shareholder proposal may evolve into a contest for corporate control. The findings highlight the importance of proactive governance reform, effective shareholder communication, and institutional measures to reduce information asymmetry, strengthen disclosure, and mitigate conflicts of interest.