The purpose of the study is to thoroughly outline how the hubris behavior of chief executive officers (CEO) is detrimental to Islamic banks’ (IBs) performance. Specifically, this study attempts to examine the role of the Sharia supervisory board (SSB), board vigilance, and CEO power in the relationship between CEO hubris behavior and decreased IBs’ performance. This study observes IBs’ performance during the period from 2014 to 2020 and develops eight models to test their determinants. Empirical testing of all models shows that CEO hubris has a detrimental impact on IBs’ performance. The moderating impact test shows the following results: firstly, the presence of SSB, which is represented by the reputation of its members, reduces the detrimental impact of hubris behavior by CEOs on IBs’ performance, while that impact, which is represented by member expertise, does not have a moderating effect. Second, the size and independence of the BOC both weaken the negative relationship between CEO hubris and IBs’ performance. Third, CEO power as represented by tenure and ownership has no moderating effect.