An organization leadership culture is the corner stone of success or failure. This paper focuses on Lean Leadership as an emergent concept introduced to many organizations where leaders are role models, empower their teams and make them accountable. In construction projects, culture is usually the combination of behaviours, attitudes, and communication inherited from previous experiences. A culture change is not welcomed unless mandated by the leadership and practiced daily. Where many factors are similar, two projects had different outcomes. A root cause analysis, on two infrastructure projects with the Public Works Authority ASHGHAL in the State of Qatar, reveals that project culture is the driving factor on a successful delivery on time and budget, and complying to quality, health and safety, and environment standards, with a public satisfaction focus. Client pre-set strategic objectives are achieved through a collaborative effort of project team where accountability is the bonding agent between promises and accomplishments. This paper summarizes a lean leadership culture adoption where it established a psychological safe working environment that delivers project to client expectations.