The standard model of particle physics is known to be incomplete due to the lack of a dark matter candidate, an explanation for the hierarchy problem, a mechanism for the generation of the baryon asymmetry, and a resolution to the strong CP problem. In this thesis, we examine possible solutions to these issues via extensions of the standard model, with a focus on the particle nature of dark matter. We detail many possible experimental probes of these proposed models, including the projected sensitivity of an upcoming telescope, and the effect of massive dark matter impacts on red-giant stellar cores. First, we propose a hidden sector extension of the minimal supersymmetric standard model that interacts with visible matter through supersymmetric kinetic mixing. This provides a natural description for weak scale dark matter whilst preserving the supersymmetric solution to the hierarchy problem. We investigate multiple probes of this dark matter through existing collider and direct detection searches, and the upcoming Cherenkov Telescope Array. We focus on the effects of R-parity violating decays of neutralinos on the dark matter cosmology and photon spectrum. The extremely low event rate of macroscopic dark matter in traditional dark matter searches warrants a look at new constraints. We show that the degenerate cores of red giant stars serve as potential detectors of macroscopic dark matter through the trigger of a core-wide ignition event, the helium flash. Data from a large population of red giant stars in the M15 globular cluster gives a novel constraint on heavy macroscopic dark matter. Lastly, we consider a model for very light dark matter, the axion, in a supersymmetric setting. We show that the rotation of the axion field can be successfully transferred, via strong sphalerons and R-parity violating interactions, to the measured baryon asymmetry of the universe. Focusing on a coupling texture motivated by grand unified theory, we can successfully recover the measured baryon asymmetry and dark matter abundance, while maintaining the axion solution to the strong CP problem. The viable region of parameter space can be probed by proton decay measurements, collider and long-lived particle searches, axion searches, and gravitational waves.