Accurate quantification of Young’s modulus in biological tissues enhances clinical accuracy in disease diagnosis, therapy, and prevention. Nevertheless, real-time, intraoperative measurement of Young’s modulus in organs remains technically challenging. We propose a novel in situ tissue elasticity assessment method based on the principles of the rebound process, where a magnetized probe is used to impact the target tissue, and Young’s modulus is calculated based on how quickly the probe rebounds. The proposed method was validated through a theoretical mechanical model and simulation. The measurement accuracy was verified by replicated measurements across different specimens. A portable handheld device was then developed and deployed for clinical feasibility validation in live animal models. Results demonstrate that the proposed method delivers accurate and reliable measurements. The proposed system offers a novel solution for Young’s modulus measurement, which can be used for intraoperative conditions such as lesion assessment during hepatectomy and breast-conserving surgery.