While prior research on gig work environments studied necessary technical skills for information systems development (ISD) professionals and how they can be developed, the improvement of non-technical skills (NTS) has been rarely explored. However, to successfully engage in the gig work economy, the need for strong NTS is increasing. Based on an experiential learning theory (ELT) perspective, we explore how ISD professionals engaging in the gig economy develop NTS by following grounded theory methodology. Our results are threefold: first, we identify crucial NTS for gig workers. Second, we uncover how these NTS are developed in different phases of adapting to working on gig economy platforms. Third, we reveal several strategies for thriving in the gig economy. Based on our findings we develop a process model of non-technical skill development and discuss this model in relation to implications for gig economy literature and practice.