Single-walled carbon nanotubes(SWNT) fluoresce in the near-infrared(n-IR) and are one of a very few classes of fluorophores with no observable photobleaching when excited at moderate fluence. We use this property to track over 10,000 individual trajectories as SWNT are incorporated into and expelled from NIH-3T3 cells over a period of up to 340min on a perfusion microscope stage. In a typical experiment, a total of 5065 trajectories(49.2%) exhibit purely convective diffusion without cellular interaction in the applied flow field. The remaining 5223 trajectories(50.8%) show distinct processes of membrane adsorption(6.2%), surface diffusion(18.4%), endocytosis(12.7%), exocytosis(5.9%) or membrane desorption(7.4%). An analysis of each mean square displacement allows, for the first time, the complete construction of the mechanistic steps experienced by SWNT as they are trafficked into and within the cell. We observe the first conclusive evidence of SWNT exocytosis in this system, and show that the rate closely matches the endocytosis rate with negligible temporal offset. Endocytosis and exocytosis together explain the previously observed aggregation and accumulation of SWNT within several mammalian cell systems.