  We investigate the temperature-dependent electronic structure of the van der
Waals ferromagnet, CrGeTe$_3$. Using angle-resolved photoemission spectroscopy,
we identify atomic- and orbital-specific band shifts upon cooling through
${T_\mathrm{C}}$. From these, together with x-ray absorption spectroscopy and
x-ray magnetic circular dichroism measurements, we identify the states created
by a covalent bond between the Te ${5p}$ and the Cr ${e_g}$ orbitals as the
primary driver of the ferromagnetic ordering in this system, while it is the Cr
${t_{2g}}$ states that carry the majority of the spin moment. The ${t_{2g}}$
states furthermore exhibit a marked bandwidth increase and a remarkable
lifetime enhancement upon entering the ordered phase, pointing to a delicate
interplay between localized and itinerant states in this family of layered
ferromagnets.
