Benchmark brown dwarf companions with well-determined ages and model- independent masses are powerful tools to test substellar evolutionary models and probe the formation of giant planets and brown dwarfs. Here, we report the independent discovery of HIP21152B, the first imaged brown dwarf companion in the Hyades, and conduct a comprehensive orbital and atmospheric characterization of the system. HIP21152 was targeted in an ongoing high-contrast imaging campaign of stars exhibiting proper-motion changes between Hipparcos and Gaia, and was also recently identified by Bonavita et al. (2022) and Kuzuhara et al. (2022). Our Keck/NIRC2 and SCExAO/CHARIS imaging of HIP21152 revealed a comoving companion at a separation of 0.37" (16au). We perform a joint orbit fit of all available relative astrometry and radial velocities together with the Hipparcos-Gaia proper motions, yielding a dynamical mass of 24_-4_^+6^MJup, which is 1-2{sigma} lower than evolutionary model predictions. Hybrid grids that include the evolution of cloud properties best reproduce the dynamical mass. We also identify a comoving wide-separation (1837" or 7.9x104au) early-L dwarf with an inferred mass near the hydrogen-burning limit. Finally, we analyze the spectra and photometry of HIP21152B using the Saumon & Marley (2008) atmospheric models and a suite of retrievals. The best-fit grid-based models have fsed=2, indicating the presence of clouds, Teff=1400K, and logg=4.5dex. These results are consistent with the object's spectral type of T0{+/-}1. As the first benchmark brown dwarf companion in the Hyades, HIP21152B joins the small but growing number of substellar companions with well-determined ages and dynamical masses.