Ongoing star formation in galaxies is mediated by the balance between feeding -- the accretion of new material from outside -- and feedback -- the energy and momentum injection from stellar processes -- in the interstellar medium. The ISM consists of three distinct gaseous phases, requiring different observational techniques to understand each phase. Modelling the multi-phase ISM requires capturing a wide range of scales and energy injection and transport processes, a task that is becoming feasible with modern (magneto)hydrodynamic simulations. I will present numerical simulations and observations of the ISM in the Milky Way and its environs tracing these feeding and feedback processes. I find that the gas microphysics keeps the ISM in the pressure regime in which all phases can coexist independent of any self-regulation processes changing the star formation rate. Feedback establishes pathways through which ionizing photons can travel from midplane O stars out of the disk, making diffuse warm ionized gas a natural consequence of star formation. On the feeding side of the star formation cycle, magnetic fields likely enable infalling gas to reach the plane and potentially contribute to ongoing star formation.