Using time-resolved x-ray magnetic linear dichroism in reflection geometry, we provide a direct, element-specific probe of the Néel vector dynamics in ${\mathrm{\text{TmFeO}}}_3$ on ultrafast timescales. Our measurements reveal that, following optical excitation, the Néel vector rotates primarily within the $ac$~plane, achieving near-complete reorientation within $\sim 20\mathrm{\text{ps}}$. This process is driven by a phonon-induced anisotropy change with a $10\mathrm{\text{ps}}$ relaxation time, accompanied by a coherent $80\mathrm{\text{GHz}}$ oscillation of the Néel vector around the dynamically evolving potential landscape. Our study demonstrates the capability of reflection-geometry soft x-ray spectroscopy to resolve intrinsic antiferromagnetic dynamics, paving the way for investigations of a broad range of functional antiferromagnets and application-relevant thin films.