Electronic screens are ubiquitous in daily life and support everyday activities in different contexts. Moderate screen use is crucial to individuals' physical and mental health in modern society, while empirical research has verified the potential of altering psychology and behavioral choices by improving micro-environmental qualities. With the hypothesis that the ever-changing contexts may influence people's screen behavior, this article explores how design interventions in these micro-environments can promote healthier and more balanced screen use. To achieve this, the fundamental step is understanding how people utilize screens in diverse contexts, including indoor and outdoor spaces in free-living scenarios. Despite its importance, current literature offers limited methodologies for precisely examining screen behaviors and their contexts simultaneously. To address this gap, this study proposes an automated method with wearable cameras and Computer Vision technologies to quantify screen exposure and related daily contexts extracted from the collected life-logging images (N = 30,186). “Indoor” and “desk” are found to be positively associated with the occurrence of screen behavior. Conversely, “greenery,” “crowd,” “travel,” and “food” exhibit robust and negative relationships with screen exposure. This study offers a new approach to objectively and automatically measure screen exposure, enhancing efficiency and reliability over conventional methods. Moreover, it establishes a replicable framework for future research on broader datasets and informs the fields of architectural and urban design on molding healthier and more balanced screen use among individuals.