Purpose: Successful entrepreneurs’ characteristics are significantly different from others. The primary purpose of this study is to analyze the effects of entrepreneurs’ characteristics categorized into innovativeness, risk-taking, network activity, and progressiveness on self-efficacy. The secondary purpose of this study is to analyze the effects of self-efficacy on needs for achievement. In addition, we attempted to analyze whether entrepreneurs’ age, revenues per month, competitiveness, and satisfaction for business moderate the relationship between self-efficacy and needs for achievement. Research design, data, and methodology: We analyzed the influences of entrepreneurs’ characteristics on self-efficacy and needs for achievement with a survey on entrepreneurs in small- and medium-sized firms. A total of 113 questionnaires were collected and used for our final analysis Results: The results of this study are as follows. First, entrepreneurs’ innovativeness, risk-taking, network activity, and progressiveness positively influenced their self-efficacy. Second, the results indicated that entrepreneur’s self-efficacy positively influenced their needs for achievement. Third, the results presented that entrepreneurs’ age, competitiveness, and satisfaction for business moderate the relationship between their self-efficacy and their needs for achievement. With respect to the moderating effects of competition intensity, there is a significant difference between low competition intensity group and high one in terms of the relationship between entrepreneurs’ network activity and their self-efficacy. With regard to the moderating effects of satisfaction for business, there is a significant difference between low satisfied group and high one in terms of the relationship between entrepreneurs’ network activity and their self-efficacy. Specifically, if they have high satisfaction for business, the moderating effect is greater than otherwise. Conclusions: The results suggested that first, if entrepreneurs make efforts to innovate products and/or services, they would have higher self-efficacy than otherwise. Second, if entrepreneurs take risks at the level where they can control the risks, they would have higher self-efficacy than otherwise. Third, if entrepreneurs maintain good relationships with partners, they would have higher self-efficacy than otherwise. Fourth, if entrepreneurs make efforts to develop new products, they would have higher self-efficacy than otherwise. Finally, if entrepreneurs hold higher self-efficacy on their own business, they would have higher needs for achievement than otherwise.