Magnesium alloys are promising biodegradable metals for orthopedic and cardiovascular applications. In the past, the critical technical barrier to the success of magnesium implants was how to slow corrosion rates. Numerous investigations showed that varying an alloy’s composition or applying surface coatings can slow corrosion. The new challenge is how to modify the corrosion rate for individual applications or patients. Once approved by a regulatory agency, modifying the composition to manipulate corrosion rates is not feasible due to the risk associated with a new material. Varying a surface coating can manipulate corrosion rates; however, coatings do not enhance the subsurface mechanical properties, and variations may be limited based on the application. Surface treatments, such as laser peening or shot peening, are a promising method to manipulate corrosion rates while improving subsurface mechanical properties. This study investigates surface integrity, such as topography, hardness, and residual stress, after shot peening Mg-Ca.