Wearable sensors can provide important human physiology and activity data and therefore have promising applications in healthcare, entertainment, and security. Here, we report the design, fabrication, and characterizations of a thin silicon film sensor for wearable sensor applications. Temperature, light, and strain sensing capabilities of the thin film of doped silicon, fabricated using a controlled spalling process, were fully characterized. An n-doped silicon thin-film sensor prepared with the spalling technology exhibited a temperature coefficient of -0.44%/°C. The sensor also showed excellent light sensing response in an illumination range from 110 to 1710 cd/mm2. The ratio of the electrical resistance changes over the applied forces was measured to be around 0.6%/N.