This dissertation reports an investigation of the personality-sales performance relationship and the effect of long and short selling cycle situations as a moderator of this relationship. Research in the area of salesperson performance has failed to establish critical theoretical foundations for testing and predicting salesperson success. Many researchers have attempted to generalize results over all categories of salespeople without consideration of those tasks and traits crucial to success in specific categories of sales employment. Three theoretical frameworks are discussed (trait, situation, interaction) and the interactionist theoretical framework is proposed as a necessary step to study the personality-sales performance relationship. Hypotheses were generated that suggested a personality characteristic may be related to sales success in one selling situation but not another. The research was conducted in a two week period by surveying salespeople from a large computer manufacturer. The three independent variables were: (1) planfulness; (2) tenacity; and (3) locus of control. Multiple dependent variables attempted to measure both objective and subjective measures of sales success. Confirmatory factor analysis was run on the sales-performance measures to check for the unidimensionality of the construct. It was found that the objective and subjective measures were not unidimensional. Based on the sales managers inexperience in rating salespeople, the objective measure of percent of quota was chosen as the best measure of sales success. In general, the data analysis supported the hypothesized effects. While the results support the premise that the personality-sales performance relationship is moderated by the long and short selling cycle situations, the tenacity hypothesis showed weak effects. Results of the dissertation are discussed with respect to the major finding and significance to personal selling research. The dissertation concludes with a discussion of the study limitations and directions for future research. / Ph. D.