  We determine the Dirac series of $GL(n,\mathbb{H})$, give the spin lowest
$K$-types of the Dirac series, and show that the spin lowest $K$-type of any
Dirac series is unique and multiplicity free. In addition, using the same
method, we show that the spin lowest $K$-type of any Dirac series in the
$GL(n,\mathbb{R})$ case is unique and multiplicity free.
