  We investigate the growth of massive quiescent galaxies at $z<0.6$ based on
the Sloan Digital Sky Survey and the Smithsonian Hectospec Lensing Survey---two
magnitude limited spectroscopic surveys of high data quality and completeness.
Our three parameter model links quiescent galaxies across cosmic time by
self-consistently evolving stellar mass, stellar population age sensitive
$D_n4000$ index, half-light radius and stellar velocity dispersion. Stellar
velocity dispersion is a robust proxy of dark matter halo mass; we use it to
connect galaxies and dark matter halos and thus empirically constrain their
coevolution. The typical rate of stellar mass growth is $\sim \! 10 \,\,
M_\odot \,\, \mathrm{yr}^{-1}$ and dark matter growth rates from our empirical
model are remarkably consistent with N-body simulations. Massive quiescent
galaxies grow by minor mergers with dark matter halos of mass $10^{10} \,\,
M_\odot \lesssim M_{DM} \lesssim 10^{12} \,\, M_\odot$ and evolve parallel to
the stellar mass-halo mass relation based on N-body simulations. Thus, the
stellar mass-halo mass relation of massive galaxies apparently results
primarily from dry minor merging.
