<p>Functional polymers have been utilized for several applications, providing various advantages like flexibility, environmental friendliness, and selectivity. This review provides an overview of the progress in functional polymer-based sensors and smart packaging for food safety. We focused on humidity, strain, and temperature sensing in the sensing applications primarily used in structural health monitoring. Moreover, the application of functional polymer in smart packaging is also discussed, closely related to the polymer's sensing performances. It was shown that various polymers and nanomaterials were utilized to produce the hybrid polymer composites, which were then used for different applications. The sensor structure and the sensing mechanisms, such as resistive and capacitive sensing, are also discussed. Furthermore, polymer-based indicators, including colorimetric and fluorescence-based sensors, have been developed to detect pH, humidity changes, and microbial contamination. Challenges, such as long-term stability, response time, and integration with wireless communication technologies, are discussed. It was determined that the functional polymers were thoroughly investigated for sensing purposes and smart packaging applications, and many innovations have been made to provide smart and sustainable solutions.</p> Graphical abstract <p></p>