Integrating the carrier tunability of a functional two-dimensional material electronic device with a direct probe of energy-and momentum-resolved electronic excitations is essential to gain insights on how many-body interactions are influenced during device operation. Here, we use microfocused angle-resolved photoemission in order to analyze many-body interactions in back-gated graphene supported on hexagonal boron nitride. By extracting the doping-dependent quasiparticle dispersion and self-energy, we observe how these interactions renormalize the Dirac cone and impact the electron mobility of our device. Our results are not only limited to a finite energy range around the Fermi level, as in electron transport measurements, but describe interactions on a much wider energy scale, extending beyond the regime of hot carrier excitations.