  Star formation has been observed to occur at globally low yet locally varying
efficiencies. As such, accurate capture of star formation in numerical
simulations requires mechanisms that can replicate both its smaller-scale
variations and larger-scale properties. Magnetic fields are thought to play an
essential role within the turbulent interstellar medium (ISM) and affect
molecular cloud collapse. However, it remains to be fully explored how a
magnetised model of star formation might influence galaxy evolution. We present
a new model for a sub-grid star formation recipe that depends on the magnetic
field. We run isolated disk galaxy simulations to assess its impact on the
regulation of star formation using the code RAMSES. Building upon existing
numerical methods, our model derives the star formation efficiency from local
properties of the sub-grid magnetised ISM turbulence, assuming a constant
Alfv\'en speed at sub-parsec scales. Compared to its non-magnetised
counterpart, our star formation model suppresses the initial starburst by a
factor of two, while regulating star formation later on to a nearly constant
rate of $\sim 1~M_{\odot}~\mathrm{yr}^{-1}$. Differences also arise in the
local Schmidt law with a shallower power law index for the magnetised star
formation model. Our results encourage further examination into the notion that
magnetic fields are likely to play a non-trivial role in our understanding of
star and galaxy formation.
