  Laszlo and Olsson constructed Grothendieck's six operations for constructible
complexes on Artin stacks in \'etale cohomology under an assumption of finite
cohomological dimension, with base change established on the level of sheaves.
In this article we give a more direct construction of the six operations for
complexes on Deligne-Mumford stacks without the finiteness assumption and
establish base change theorems in derived categories. One key tool in our
construction is the theory of gluing finitely many pseudofunctors developed in
arXiv:1211.1877. As an application, we prove a Lefschetz-Verdier formula for
Deligne-Mumford stacks. We include both torsion and $\ell$-adic coefficients.
