Tissue characterization method in optical coherence tomography (OCT) for in situ histology of soft tissues is presented and demonstrated for mice skin. OCT allows direct noninvasive visualization of subsurface anatomy. It is currently used for in situ investigation of lesions in skin, vessels, retinal layers, oral, and bronchial cavitities. Although OCT images present high resolution information about tissue morphology, reporting requires a reader experienced in interpretation of the images, viz., identification of anatomical layers and structures constituting the organ based on OCT speckle appearance. Our approach characterizes tissues through transfer learning of tissue energy interaction statistical physics models of ballistic and near-ballistic photons. The clinical information yield with our approach is comparable to conventional invasive histology. On cross evaluation with a mice model experiment, the epidermis, papillary dermis, dermis, and adipose tissue constituting the mice skin are identified with an accuracy of 99%, 95%, 99%, and 98%, respectively. This high accuracy of characterizing heterogeneous tissues using OCT justifies the ability of our computational approach to perform in situ histology and can be extended to regular clinical practice for diagnosis of vascular, retinal, or oral pathologies.