Uncertainties in ocean mixing parameterizations are primary sources for ocean and climate modeling biases. Due to lack of process understanding, traditional physics-driven parameterizations perform poorly in the tropics. Recent advances in deep learning method and new availability of long-term turbulence measurements provide an opportunity to explore data-driven approaches to parameterize oceanic vertical mixing processes. Here, we describe a novel parameterization based on an artificial neural network trained using a decadal-long time record of hydrographic and turbulence observations in the tropical Pacific. This data-driven parameterization achieves higher accuracy than current parameterizations, demonstrating good generalization ability under physical constraints. When integrated into an ocean model, our parameterization facilitates improved simulations in both ocean-only and coupled modeling. As a novel application of machine learning to the geophysical fluid that employs turbulence measurements, these results show the feasibility of using limited observations and well-understood physical constraints to construct a physics-informed deep learning parameterization for improved climate simulations.