To understand how the present day universe came to be, we must understand how the massive structures in which we live formed and evolved over the preceding billions of years. An important consideration is the growth of the most massive galaxies, called brightest cluster galaxies (BCGs). Their relaxed structures, old stellar populations, and central location within their clusters favor a high redshift formation model. However, star-forming BCGs have been observed at much more recent epochs. Addressing this evolutionary complexity, my dissertation consists of four studies to investigate the growth rates of BCGs with redshift, and how they relate to the growth of the general galaxy population. In my first two papers (Cooke et al. 2016, 2018), I present multiwavelength studies of BCG star formation rates and stellar masses out to z ~ 1, and find that in-situ star formation in my sample is consistent with overall quiescence, and star-forming BCGs remain very rare at low redshift. My third paper (Cooke et. al 2019a in prep.) identifies BCG progenitors out to z ~ 3 using cumulative comoving number density tracks from the Illustris Project. We identify three phases of growth, limiting the star-formation dominated epoch to z > 2.25. Finally, my fourth paper (Cooke et al. 2019b in prep.) places the preceding results in context by measuring the correlation between star formation rate and stellar mass down to the mass completeness limit in COSMOS from 0 < z < 3.5.