Cardiovascular diseases (CVDs) continue to be the globe’s leading cause of death, and therefore, there is a need for low-cost, long-term cardiac monitoring technologies especially in low-resource environments. Current wearable ECG technologies are limited by cost, proprietary design, and single-functionality. We introduce ECGGoDevice, a low-cost, portable, multi-functional, wearable device with real-time ECG monitoring, heart rate variability (HRV) analysis, fall detection, and step counting in one platform. The system utilizes a high-fidelity analog front-end and inertial sensing to provide mobility-aware cardiac monitoring. A 44-subject validation trial compared ECGGoDevice with a clinical-grade Shimmer3 ECG system and the Fitbit Sense 2 on 12 standard time-domain HRV measures and 10-day step count. The ECGGoDevice demonstrated good agreement (all p > .05; r > .93) with Shimmer3, and high correlation in step count measure (r = .94). With clinically robust signal quality, real-time wireless transmission, and safety alert capability, ECGGoDevice provides a scalable solution for longitudinal cardiac and mobility monitoring especially for eldercare and underserved communities.