It is widely accepted by researchers that leaders play important roles in improving employee performance. However, consensus on adopting leadership styles is subjected to argumentative rigour. Previous studies have found evidence that directive leadership style is effective in resolving team's task and role ambiguity; in improving performance and core task performance. Among other leadership behaviours, supportive leadership is identified as an effective leadership approach that heeds employees' personal needs; providing them with social and emotional support. Directive and supportive leadership styles are found to complement each other resulting in improved performance outcomes. Path-Goal Theory proposes both leadership behaviours are among the rooted four leadership styles, namely: directive, supportive, participative, and achievement-oriented, that optimizes the employee and work environment to achieve a goal. Several factors including motivation and organisational citizenship behaviour are perceived to determine the appropriateness of leadership styles to be employed situationally. This paper presents a conceptual framework that depicts the mediating effect of these two factors on the relationship between leadership styles and task performance. Empirical results will be presented in the sequel to this theoretical study.