The nature of galaxy evolution from the early Universe to the present day is intricately linked to large-scale environment: the environments of galaxies are expected to play a critical role in the development of their morphologies, star formation activity, and the activity of their central Super Massive Black Holes (SMBHs). Large scale environment can strongly and rapidly affect gas reservoirs which are a prerequisite for both star formation and SMBH activity. We would expect the effect of environment to be most pronounced in massive galaxy clusters, where both the density of the intracluster medium and number density of galaxies are the highest. This has indeed been established for star formation activity in the local and intermediate redshift universe, where dense, cluster environments are more likely to host elliptical, quiescent galaxies. However, the impact of the cluster environment on SMBH activity has been significantly less clear. At high redshift, the impact of clusters on galaxy activity is even less well understood. This is due to both a decline in the number of massive clusters at high redshift as well as increasing observational difficulty in reliably identifying and characterizing both the clusters themselves and their member galaxies. This dissertation tries to bring some clarity to these unknowns. First, we present an analysis of SMBH activity in a sample of massive clusters at intermediate redshift where we confirm a dependence of this activity on cluster mass. Second, we describe the spectroscopic characterization of one of the highest redshift galaxy clusters ever discovered, existing at a lookback time of more than 10 billion years. We model the stellar population of its member galaxies and trace their formation back to the cosmic dark ages, when the Universe was only 370 million years old. Finally, we do a deep dive into this cluster's galaxy population and find it to be remarkably similar to that of clusters in the local universe. We identify a tremendously enhanced quiescent fraction relative to the field and find evidence for accelerated size-evolution in these quiescent galaxies.