Objective This study aimed to explore whether screen time and the screen type impacted various health aspects of children, including physical activity (PA), sleep quality, and eating habits. Additionally, we investigated whether children’s eating behavior while using electronic devices affects their physical and mental health. Methods We conducted an online survey asking for screen use (duration, type, and purpose), PA, eating habits, sleep problems, and level of depression. The participants were children between the ages of 3 and 7 years, and the survey was answered by the participants’ parents from March 3 to March 20, 2021. Results A screen time of ≥2 h in children was associated with various clinical characteristics, such as body mass index (BMI), sleep problems, depression, decreased PA, and unusual eating habits. Children’s food eating behavior while using electronic devices was predicted by a total screen time ≥2 h, smartphone screen time ≥2 h, sleep problems, owning electronic devices, and eating unhealthy food. Conclusion There was an interplay among children’s PAs, eating behaviors, depression, sleep problems, and screen time in this pandemic era. Therefore, guiding children on the correct use of electronic devices and helping them eat healthy are paramount during this COVID-19 pandemic.