In the past decades, software organizations have been relying on implementing process improvement methods to advance quality, productivity, and predictability of their development and maintenance efforts. However, these methods have proven to be challenging to implement in many situations, and when implemented, their benefits are often not sustained. Commonly, the workforce requires guidance during the initial deployment, but what happens after the guidance stops? Why do not traditional improvement methods deliver the desired results? And, how do we maintain the improvements when they are realized? In response to these questions, we have combined social and organizational learning methods with Lean's continuous improvement philosophy, Kaizen, which has resulted in an IDKL model that has successfully promoted continuous learning and improvement. The IDKL has evolved through a real-life project with an industrial partner; the study employed ethnographic action research with 231 participants and had lasted for almost 3 years. The IDKL requires employees to continuously apply small improvements to the daily routines of the work-procedures. The small improvements by themselves are unobtrusive. However, the IDKL has helped the industrial partner to implant continuous improvement as a daily habit. This has led to realizing sustainable and noticeable improvements. The findings show that on average, Lead Time has dropped by 46 percent, Process Cycle Efficiency has increased by 137 percent, First-Pass Process Yield has increased by 27 percent, and Customer Satisfaction has increased by 25 percent.