Job insecurity has been theorized as an antecedent of participation in learning activities. However, prior research has failed to establish a consistent relationship between job insecurity and learning participation. Drawing from the career self-management framework, we argue that separating firm-supported formal learning and employee-directed formal learning could help map the motivational reaction when perceiving job insecurity onto various choices of learning participation. A three-factor motivational reaction scale (i.e., job preservation motivation, internal proactive coping motivation, and external proactive coping motivation) was validated with four subject experts and 251 participants on Prolific. Then, we surveyed 326 participants through Prolific across five months and found that employees experiencing heightened job insecurity participated in more firm-supported formal learning programs because of the desire to find a new job in a different organization. We discuss contributions to the literature on career self-management framework, job insecurity, and motivation in formal learning participation.