The focus of this study is to examine the effect of fundamental pocket geometries of a cylindrical roller bearing (CRB) cage on its lubrication and friction performance. Lubrication in bearings presents an interesting tradeoff, with excessive lubrication resulting in high friction and fluid drag, while poor lubrication inherently results in wear and component damage. Three cage pockets of varying conformity with the roller were investigated to determine pocket friction due to fluid shear as well as lubricant availability within the pocket. A custom Bearing Cage Friction Test Rig (BCFTR) was utilized to isolate a single roller within a cage pocket geometry. The BCFTR was configured with a 6-axis load cell to accurately measure friction developed between the roller and pocket, while the roller speed was controlled through a precise servo motor. A lubricant sealing enclosure was installed around the roller to control the lubricant fill condition during testing. The enclosure was designed to include swappable, transparent cage inserts with adjustable roller pocket clearances. Testing was conducted for a range of roller speeds, pocket clearances, and lubricant fill conditions, and a high-speed camera was used to capture lubricant flow within the roller–pocket gap. A multiphase computational fluid dynamics (CFD) model was developed for an equivalent geometry, matching the range of test conditions. The robust model was able to accurately predict both the experimentally measured pocket friction and the imaging of the pocket lubrication state. Through the study, cage pocket conformity was determined to have a prominent effect. Reducing pocket conformity aids in minimizing pocket friction. However, the larger pocket inlet and outlet zones resulting from a low-conformity design promote high recirculation, which generates aeration within the lubricant. Furthermore, a low-conformity pocket design faces challenges in retaining the lubricant in the roller–pocket contact.