The aim of the present study was to investigate the impact of two task-processing conditions (10 minutes of pre-task planning time and content familiarity of the task) on spoken performance in terms of the fluency, complexity, and accuracy in a narrative task. The subjects were 20 Korean undergraduate students with a high language proficiency. The results of the two-way interaction effect between the planning and familiarity of the MANOVA were significant in terms of pause length. The univariate test of familiarity in an unfamiliar condition for subordinate clauses in the MANOVA test was significant. The study also found a trade-off effect between complexity and accuracy in terms of the effects of planning time in planned and unfamiliar conditions. These results suggest that the performance of learners could be varied depending on the different combinations of task-processing conditions even in a single narrative task.