The KArlsruhe TRItium Neutrino (KATRIN) Experiment aims for the determination of the effective mass of the electron-antineutrino. KATRIN uses a strong, gaseous, windowless tritium source for precision spectroscopy of the β-electrons. The 70-m-long experiment has been set up at the Tritium Laboratory Karlsruhe (TLK) and was commissioned with traces of tritium during two measurement campaigns in 2018. In spring 2019, the first campaign with full source luminosity started. KATRIN uses a complex gas-handling system called Loops for stabilized injection of tritium into the source and tritium gas handling. It also makes use of the unique facilities and possibilities found at the TLK for gas handling, cleanup, and purification. This paper describes the integration of KATRIN into TLK’s existing infrastructure and the current status of the experiment and concludes with a summary of the tritium measurements.