The field of executive coaching has grown in popularity as a developmental tool for leaders. With the potential for a leadership continuity gap and the desire for organizations to strengthen leadership talent pools to prepare for succession planning, there is a need for empirical research regarding the effectiveness of executive coaching. The aim of this mixed method study was to explore the factors that contribute to successful coaching outcomes. The combination of an online survey of 68 high potential leaders and follow up interviews with 40 of those same leaders yielded information about the coaching experience. The results showed a correlation between the number of years a leader was with the company and his or her perception of a positive coaching experience. In addition, the total amount of time the coach and the leader spent together was correlated with the perception of a positive coaching experience. Finally, most leaders noted that exceptional coaches demonstrated professionalism in several ways, such as listening to the client, showing an interest in the client and their development, and providing advice and helpful suggestions. A better understanding of the factors that promote successful outcomes for high potential leaders will assist coaches in having positive impact on client and organizational performance. This study is unique in that it examines coaching in the context of a larger intervention, a leadership development program, using HR professionals as internal coaches with high potential leaders. For organizations using coaching in this fashion, this study addresses gaps in the literature, which was an impetus for this research. Additional research might be valuable on how coaching clients define a successful coaching outcome, a client's readiness to change, the coach-client relationship, and factors that promote sustained behavior change in a leader.