We have made Ni films by electron beam evaporation for use as a variable delay surface acoustic wave (SAW) device. The films have been characterized by static magnetization and magnetostriction measurements as well as by measurements of SAW phase shift attenuation in applied magnetic fields. A unified theoretical treatment of the field dependence of all the measured quantities is developed, based on a free-energy expression containing Zeeman, demagnetization, anisotropy, magnetoelastic, and elastic energy terms. We introduce an analytical technique by which a quantitative measure of a film inhomogeneity such as the variance of the uniaxial magnetic anisotropy field may be deduced from static field experiments. The dynamic field analysis establishes basic analytical expressions for phase shift and attenuation of SAW devices which may serve as a useful guidance to the design of practical surface acoustic wave devices. Reasonable agreement between experiments and theoretical predictions of these calculations is obstained.