  We explore and discount the hypothesis that the strong, continual
H$\alpha$-emitting T dwarf 2MASS J12373919+6526148 can be explained as a young,
low gravity, very low mass brown dwarf. The source is already known to have a
marginally-fainter absolute magnitude than similar T dwarfs with trigonometric
parallax measurements, and has a tangential velocity consistent with old disk
kinematics. Applying the technique of Burgasser, Burrows & Kirkpatrick on new
near infrared spectroscopy for this source, estimates of its {\teff}, $\log{g}$
and metallicity ([M/H]) are obtained. 2M 1237+6526 has a {\teff} $\approx$
800-850 K. If [M/H] is solar, $\log{g}$ is as high as $\sim$5.5 (cgs) and this
source is older than 10 Gyr. We find a more plausible scenario to be a modestly
subsolar metallicity ([M/H] = -0.2) and moderate $\log{g}$ $\sim$ 5.0, implying
an age older than 2 Gyr and a mass greater than 0.035 M$_{\sun}$. The
alternative explanation of the unique emission of this source, involving an
interacting, close, double degenerate system, should be investigated further.
Indeed, there is some evidence of a {\teff} $<$ 500 K companion to 2M 1237+6526
on the basis of a possible $Spitzer IRAC$ [3.6]--[4.5] color excess. This
excess may, however, be caused by a subsolar metallicity.
