With the increasing levels of digital transformation, focus on digital identities of individuals is increasingly getting prominence. It is the information captured as part of the identity surrounding the citizens which decides what services and products one is entitled to and can access. At present, there are still around 1.1 billion people in the world without any official identity. To address this concern, United Nations through its 16th Sustainable Development Goals (SDGs) recommended governments to provide their citizens with unique identities by 2030. India's Aadhaar is one significant step in this direction as it has already reached over 1 billion enrolments in India. However establishing a national digital identity program successfully requires expertise, time, and huge financial commitments. This paper takes Aadhaar as a case study and uses Design Theory (DT) and Critical Success Factor theory (CSF) as a theoretical lens and attempts to evaluate design and execution choices made during the tenure of the project. The study also identifies and prioritizes primary goals of Aadhaar based on the secondary data, expert opinion through a Focus Group Discussion (FGD) and subsequently systematic prioritization using mixed research methodologies.The expert opinion from the FGD was analyzed using the Best-Worst method (BWM), followed by the Total Interpretive Structural Modeling (TISM) method and Matrix of Cross Impact Multiplications Applied to Classification (MICMAC) analysis. The study identified uniqueness, security and privacy as the top priority goals in an identity system and is 11 times more crucial than scalability which is identified to be of lesser priority. These findings from this study could be considered as a reference for other countries that aim to develop and implement digital identity for its citizens.