In extant research, scholars have treated proactive career behavior (e.g., career exploration) primarily as a consequence of future work self. Yet, emerging evidence provides support for a relationship in the opposite direction, suggesting that career exploration may also be an antecedent. Using a cross-lagged panel design, we empirically tested the reciprocal relationship between future work self and career exploration. In Study 1, we measured both future work self and career exploration at two time points with an 8-week lag among 133 Chinese university students. Results showed that future work self and career exploration are reciprocally related over time. In Study 2 (N = 228), with a longer time lag (12 weeks), results showed that career exploration (Time 1) is significantly related to future work self (Time 3), but not vice versa. Moreover, career adaptability (measured in week 8, Time 2) mediates the reciprocal effects between future work self and career exploration. We discuss theoretical and practical implications.