In vitro, drug assessment holds tremendous potential to success in novel drug development and precision medicine. Traditional techniques for drug assessment, however, face remarkable challenges to achieve high speed, as limited by incubation‐based drug delivery (>several hours) and cell viability measurements (>1 d), which significantly compromise the efficacy in clinical trials. In this work, a nano‐electroporation‐DNA tensioner platform is reported that shortens the time of drug delivery to less than 3 s, and that of cellular mechanical force analysis to 30 min. The platform adopts a nanochannel structure to localize a safe electric field for cell perforation, while enhancing delivery speed by 103 times for intracellular delivery, as compared to molecular diffusion in coculture methods. The platform is further equipped with a DNA tensioner to detect cellular mechanical force for quantifying cell viability after drug treatment. Systematic head‐to‐head comparison, by analyzing FDA (food and drug administration)‐approved drugs (paclitaxel, doxorubicin), demonstrated the platform with high speed, efficiency, and safety, showing a simple yet powerful tool for clinical drug screening and development.