We present the discovery of TOI-1994b, a low-mass brown dwarf transiting a hot subgiant star on a moderately eccentric orbit. TOI-1994 has an effective temperature of 7700_-410_^+720^K, Vmagnitude of 10.51mag and logg of 3.982_-0.065_^+0.067^. The brown dwarf has a mass of 22.1_-2.5_^+2.6^MJup, a period of 4.034days, an eccentricity of 0.341_-0.059_^+0.054^}, and a radius of 1.220_-0.071_^+0.082^RJup. TOI-1994b is more eccentric than other transiting brown dwarfs with similar masses and periods. The population of low-mass brown dwarfs may have properties similar to planetary systems if they were formed in the same way, but the short orbital period and high eccentricity of TOI-1994b may contrast this theory. An evolved host provides a valuable opportunity to understand the influence stellar evolution has on the substellar companion's fundamental properties. With precise age, mass, and radius, the global analysis and characterization of TOI-1994b augments the small number of transiting brown dwarfs and allows the testing of substellar evolution models.