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.
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