The 4 August 2020 Port of Beirut blast caused material damage to an estimated 77,000 apartments located across 10,000 buildings within a 3 km radius of the blast, impacting around 300,000, people predominantly in the municipality of Karantina, which is situated adjacent to the Port of Beirut. The blast shed light on the instability and unsustainable development approach of the city of Beirut since well before the French mandate circa 1921–1940. The impact of the blast provides an opportunity to reassess the relationship between many relevant aspects of the city planning including but not limited to: the relationship of the city to its suburbs, waterfront, and city center; the lack of local planning and cross sectorial master plans; the preservation of the heritage versus the complexity of its urban development; the city growth and increased haphazard urbanization; the infrastructure/service systems that have over the years become increasingly deficient; the lack of public spaces; impacts on urban climate; and the urban divide and inequality that have only grown deeper since the blast, all of which have a combined and adverse impact on the quality of city life. This paper analyzes the most suitable indicators that one must highlight within the context of Beirut city to propose a better and sustainable quality of life with a focus on areas that were significantly impacted by the recent POB blast, namely Karantina. Examples of indicators which were analyzed include sustainable urban design, open spaces, heritage, infrastructure, and urban fabric. The results indicated that the following four main urban design features help improve the quality of life in Karantina, including: (i) connecting areas of Karantina and Mar Mkhael through the reactivation of vacant lots; (ii) reactivation of Ibrahim Bacha and El-Khodr Streets; (iii) redefining the historical El Khodr Mosque boundary and reclaiming its role as an urban landmark; and (iv) integration of classified built heritage. These parameters are necessary to improve the quality of life. The benefits of community participation are also assessed in the improvement and sustainable planning of the city of Beirut.