We demonstrate the ability to generate ultra-high-frequency sequences of broadly wavelength-tunable, high-intensity laser pulses using a custom-built optical parametric oscillator pumped by the third-harmonic output of a “burst-mode” Nd:YAG laser. Burst sequences consisting of 6–10 pulses separated in time by 6–10\text{\hspace{0.17em} μs} are obtained, with average total conversion efficiency from the \text{355 \hspace{0.17em} nm} pump to the near-IR signal and idler wavelengths of \sim \text{33\%} . Typical individual pulse output energy for the signal and idler beams is in the range of \text{4}–\text{6 \hspace{0.17em} mJ} , limited by the available pump energy. Line narrowing is demonstrated by means of injection seeding the idler wave using a low-power external-cavity diode laser at \text{827 \hspace{0.17em} nm} . It is shown that seeding reduces the time-averaged linewidth of both the signal and idler outputs to \sim \text{300 \hspace{0.17em} MHz} , which is near the \text{220 \hspace{0.17em} MHz} Fourier transform limit. Line narrowing is achieved without recourse to active cavity stabilization.