  The \textit{heavy-fluxonium} circuit is a promising building block for
superconducting quantum processors due to its long relaxation and dephasing
time at the half-flux frustration point. However, the suppressed charge matrix
elements and low transition frequency have made it challenging to perform fast
single-qubit gates using standard protocols. We report on new protocols for
reset, fast coherent control, and readout, that allow high-quality operation of
the qubit with a 14 MHz transition frequency, an order of magnitude lower in
energy than the ambient thermal energy scale. We utilize higher levels of the
fluxonium to initialize the qubit with $97$\% fidelity, corresponding to
cooling it to $190~\mathrm{\mu K}$. We realize high-fidelity control using a
universal set of single-cycle flux gates, which are comprised of directly
synthesizable fast pulses, while plasmon-assisted readout is used for
measurements. On a qubit with $T_1, T_{2e}\sim$~300~$\mathrm{\mu s}$, we
realize single-qubit gates in $20-60$~ns with an average gate fidelity of
$99.8\%$ as characterized by randomized benchmarking.
