  Control and manipulation of single charges and their internal degrees of
freedom, such as spins, is a fundamental goal of nanoscience with promising
technological applications. Recently, atomically thin semiconductors such as
WSe$_2$ have emerged as a platform for valleytronics, offering rich
possibilities for optical, magnetic and electrical control of the valley index.
While progress has been made in controlling valley index of ensemble of charge
carriers, valley control of individual charges, crucial for valleytronics,
remains unexplored. Here, we provide unambiguous evidence for localized holes
with net spin in optically active WSe$_2$ quantum dots (QDs) and control their
spin-valley state with the helicity of the excitation laser under small
magnetic field. We estimate a lower bound on the valley lifetime of a single
charge in QD from recombination time to be $\sim$ nanoseconds. Remarkably,
neutral QDs do not exhibit such a control, demonstrating the role of excess
charge in prolonging the valley lifetime. Our work extends the field of 2D
valleytronics to the level of single spin-valley, relevant for quantum
information and sensing applications
