Star formation in galactic disks is regulated by the competition between gravity and stellar feedback. In pressure-regulated, feedback-modulated (PRFM) theory, the star formation rate adjusts until feedback-modulated thermal, turbulent, and magnetic support balances the vertical weight of the interstellar medium. I will describe the physical basis of PRFM and introduce the feedback yield, the ratio of total pressure to star formation rate surface density. I will then show how TIGRESS-family simulations of the multiphase ISM, incorporating self-gravity, magnetic fields, star formation, stellar feedback, radiation, and photochemistry, have tested the theory and calibrated its feedback yields across galactic environments. Finally, I will discuss how these resolved-physics results are being translated into new subgrid star formation models for galaxy and cosmological simulations, providing a path from local ISM physics to more predictive models of galaxy formation.
