Chimeric antigen receptor (CAR) T cells are genetically engineered T cells that have been used to target cancer-associated antigens [1]. The profound success of CAR T cells in treating hematological malignancies (e.g. leukemia by targeting CD19) has led to the FDA approval of three CAR T cell products [2]. CAR T cells are primarily engineered via viral methods which insert the CAR transgene into random locations in the genome resulting in varied expression and signal activation of the CAR [3]. As a result, CAR T cell performance can vary greatly from cell to cell even within the same batch, due in part to the heterogeneity of CAR activity within the gene-modified T cell population [4]. Therefore, to better ensure that manufactured CAR T cells will result in cancer remission, improvements to the manufacturing process must be made to certify that the live cellular products will act accordingly once they are delivered to the patient [5]. This thesis aims to engineer precise control over the location of integration and copy number afforded by CRISPR-Cas9 gene editing tools to create more homogenous expression of the CAR in the manufactured CAR T cell population, resulting in less variance in potency of individual CAR T cells. First, I describe the manufacture and measurement of expression and function within virally generated and CRISPR-Cas9 generated CAR T cell products. Next, I detail the in vitro functional analysis of CAR T cells within microwell co-cultures with target cancer cells to allow for measure of in vitro activity of the CAR+ cells and acquire relevant parameters for mathematical models. Finally, I share the results of in vivo testing and computational modeling of CAR T cell therapies within murine xenograft models. This work demonstrates the value of precise gene editing in CAR T cell manufacture, and its influence on quality assurance and quality control (QA/QC) methods of CAR T cell products.