Digital holographic microscopy (DHM) with 3D microscopic imaging capability is attractive for biological sampling, particle identification, and surface topographic profiling. The Michelson (Linnik) optical configuration along with microscope objectives is used to create a hologram with the reflections of a sample of 3D spatial structures. Instead of instantaneous volume recording of the hologram in a holographic film, a digital camera is used to sequentially record four phase-step holograms in 2D format, namely the digital holograms (DHs). A piezoelectric actuator was added to implement the formation of the four-phase-step DHs. Using a four-image phase-shifted algorithm, the 3D microscopic image of the object can be extracted. The recording of the DHs is fast, 28 ms, and the phase retrieval computation is fast as well, 24 ms. The DHM has been utilized to examine the surface topography of a lithography sample showing field of view of 312 μm × 234 μm, axial resolution of 3.31 nm, lateral resolution of 488 nm, and a maximum topography height of 270 nm.