The rapid spread of Smart Internet of Things (IoT) systems across healthcare, transportation, and smart homes has transformed human-technology interaction while introducing significant security vulnerabilities. This research identifies and analyzes critical security challenges in Smart IoT ecosystems and proposes comprehensive mitigation strategies. The investigation reveals a diverse device landscape lacking standardized security protocols, leaving systems susceptible to malware, unauthorized access, and denial-of-service attacks, with many devices continuing to operate with unchanged default passwords. The study highlights the necessity for robust security measures including encryption, secure boot processes, and regular software updates. A multi-layered security approach is advocated, requiring collaboration among manufacturers, users, and regulatory bodies to establish industry-wide standards and enhance user awareness regarding security best practices. The research further examines how advanced technologies such as machine learning and blockchain can improve threat detection capabilities and data integrity in IoT environments. This paper underscores the urgency of addressing IoT security challenges to foster trust in these innovative technologies. As connected devices continue to proliferate, ongoing research and cooperative efforts across stakeholders are essential for developing effective security strategies. The findings contribute to the evolving discourse on IoT security by providing actionable insights for industry stakeholders seeking to protect increasingly interconnected digital ecosystems.