Despite many investigations concerning the outcomes of affective organizational commitment (AC) in the workplace, very few studies so far have analyzed the long‐term development of AC within individuals over time. Existing research either focused on individuals' initial employment stage or was restricted to a specific organizational context. To provide supplemental evidence, we examined the development of AC over 6 years in a group of employees that had passed their initial year of employment. Results from a factorial‐invariant latent change score model with 1004 individuals from different organizations in Korea indicated an overall increase of AC over time. To further explore why individuals differ in their growth patterns, we related intra‐individual changes of AC to individuals' income in two aspects: levels and changes. Cross‐lagged regression models firstly revealed positive reciprocal relationships between AC level and income level, showing an individual accumulation of AC over time. Furthermore, the study showed a significantly positive impact of income changes on AC changes, but not vice versa, illustrating the transition of AC at the individual level. Theoretical and practical implications of these findings are discussed, revealing future research on the development of commitment. Copyright © 2016 John Wiley & Sons, Ltd.