The fast development of smart cities predominantly relies upon the consummate integration of Internet of Things (IoT) devices to manage the cities in a resourceful way and enhance the quality of life. However, massive deployments of IoT devices suffer from security and energy consumption drawbacks. This paper introduces a new IoT protocol enhanced with Fuzzy Logic and Blockchain technology to alleviate these issues. The presented protocol exploits the advantages of Fuzzy Logic for optimal dynamic management of energy consumption by considering real-time data in the decision-making process to improve the operational efficiency of IoT devices under various circumstances. Moreover, Blockchain technology is exploited to provide a secure and decentralized data transmission and storage platform, preventing unauthorized access or manipulation and reducing other risks in IoT applications such as cyber-attacks and privacy intrusion. By conducting comprehensive simulations and experimental work, it is shown that the proposed protocol performs better in improving the Quality-of-Service metrics, saving power consumption, prolonging network lifetime, reducing delivery response time, and ensuring high-level security compared to existing popular IoT routing protocols.