A 1st-principles-inspired physiological model was developed that can predict the redistribution of fluid and albumin in the patient after thermal injury. The key components of the model include volume kinetics, renal function, and burn-induced perturbations in circulatory physiology. The model was developed in such a way that it can be fully characterized by the patient weight, height, and total burn surface area (TBSA) as well as a small set of model parameters to be individualized to predict the patient's response to thermal injury and resuscitation. Based on the underlying physics and constraints of organs, new mathematical functions were developed to describe the renal function and lymph return. A novel approach was employed to implement the effect of burn on the pertinent physiology of patients' body. The model was identified and tested using two groups of sheep undergoing burn injury and resuscitation. The results suggested that the model can boast acceptable accuracy in reproducing experimentally observed plasma volume and urinary output despite its simplicity. Such a model, after meeting the requirements on accuracy and physiological credibility, may facilitate the validation and testing of burn resuscitation protocols and closed-loop decision support systems.