This study has empirically analyzed how critical success factors of Six Sigma affect differentially Six Sigma quality performance related to electronics industries in Korea by the CEO who regularly leads the Six Sigma practice and by the key driving force such as MBB, BB and BG, which leadership type amongst CEO’s leadership influences more Six Sigma performance, and how training & education, supportive infrastructure, practice experience of prior quality programs and Black Belt operation, strategic drive scope have an effect on Six Sigma performance depend on the company size. For this, we have given questionnaire to the key personnel of Six Sigma who has worked in small and medium sized company as well as big sized company related to electronics industries in Korea. As the result of empirical analyses on the basis of those data, regardless of company size, CEO should show strongly transformative leadership amongst the key success factors of Six Sigma. That is, it is actually identified that the CEO of big sized company who display the “charismatic” elements leadership and the leaders who in the small and medium sized company display the “individual concern” elements leadership more positively make effect on the quality performance of Six Sigma. Also we found that the key factor of Six Sigma implementation, efficient operations of black belt make positive effect on the quality performance of Six Sigma. Moreover, small and medium sized company needs to consider system and organizationally compensation plan of fundamental infra computerized system and/or working team operation, incentive system performance as well as education & training, black belt operation are also required to improve systematically.