We present a single-objective light-sheet microscope, also known as an oblique-plane microscope, that uses a bespoke glass-tipped tertiary objective and improves the resolution, field of view, usability, and stability over previous variants. Owing to its high numerical aperture optics, this microscope achieves the highest lateral resolution in light-sheet fluorescence microscopy, and its axial resolution is similar to that of Lattice Light-Sheet Microscopy. Given this performance, we demonstrate high-resolution imaging of clathrin-mediated endocytosis, vimentin, the endoplasmic reticulum, membrane dynamics, and natural killer cell-mediated cell death. Furthermore, we image biological phenomena that would be otherwise challenging or impossible to perform in a traditional light-sheet microscope geometry, including cell migration through a confined space within a microfluidic device, photoactivation of PI3K, and diffusion of cytoplasmic rheological tracers at a volumetric rate of 14 Hz.