We provide a full numerical characterization of non-Markovian quantum decoherence for a two-level (qubit) system coupled to a tailorable reservoir by studying the influence of different factors, such as system–reservoir coupling and temperature. The necessity of a decoherence analysis from short to long time ranges and for a large set of parameters are fundamental requirements for quantum information processing in order to produce a controlled conditional quantum dynamics. We show how the Feynman–Vernon influence functional technique can be used in order to obtain a numerical algorithm that enables a full characterization of non-Markovian processes. This analysis paves the way for modeling the prevention and control of decoherence in solid-state systems with ultrafast dynamics and strong environmental coupling.