Abstract: This study involved 51 K-12 principals throughout California. The problem was looking at the extent of the influence of education and training on the Staff Development Practices of these principals. A professional profile was developed based on their Administrative Credential Program Education, training while employed as a principal, and the number of years as a classroom teacher and principal. A mixed methods design was used to provide both quantitative and qualitative findings. Surveys were sent out to 7 school districts throughout California with 51 principals responding. Correlations and t tests were both run on the collected data to determine quantitative results. Three questions were asked concerning years of service and their comments on the greatest influences on their staff development practices providing qualitative results. The training period while employed as a principal was found to have the greatest statistical significance on the influence on Staff Development Practices. The Administrative Credential period resulted in half as many topics found to have statistical significance as training. The non-statistical results showed the principals rated education and training topics with the same 5 highest rated sums showing no greater influence during the training period. The comments portion of the survey indicated a clear contradiction to rated sums. Comments from the principals delivered strong feelings that professional development activities were the greatest influence on their Staff Development Practices. There was no correlation found between the years of service and Staff Development Practices, with the exception of 1 of 14 topics. Reform/Collaboration reflected statistical significance and a relationship to years as a principal.