The process whose specific outcome is the progression of a posterior lateral line neuromast hair cell over time, from its formation to the mature structure. A neuromast hair cell is a hair cell that acts as a sensory receptor of the neuromast; it is morphologically polarized as a result of the relative position of the single kinocilium and the clusters of stereocilia on its apical surface. Cell development does not include the steps involved in committing a cell to a specific fate.