Intense four- and five-photon ultraviolet upconversion processes through sensitization of ${\mathrm{Tm}}^{3+}$ ions in transparent ${\mathrm{SiO}}_2–{\mathrm{Al}}_2{\mathrm{O}}_3–\mathrm{NaF}–{\mathrm{YF}}_3$ glass ceramics triply doped with ${\mathrm{Tm}}^{3+}∕{\mathrm{Yb}}^{3+}∕{\mathrm{Nd}}^{3+}$ under $796\mathrm{nm}$ excitation were investigated. Judd–Ofelt analyses evidenced the incorporation of rare-earth ions into the precipitated $\beta \text{-}{\mathrm{YF}}_3$ nanocrystals. In contrast with the triply doped one, no ultraviolet upconversion luminescence was observed in the ${\mathrm{Tm}}^{3+}∕{\mathrm{Nd}}^{3+}$ codoped glass ceramic, indicating that ${\mathrm{Yb}}^{3+}$ acts as bridging ions to enhance the energy transfer efficiency between ${\mathrm{Nd}}^{3+}$ and ${\mathrm{Tm}}^{3+}$ . Based on the pumping power dependence of luminescence, upconversion mechanisms were proposed.