Business processes in workflows comprise of an ordered sequence of tasks and decisions to accomplish certain business goals. Each decision point requires the input of a decision-maker to distill complex case information and make an optimal decision given their experience, organizational policy, and external contexts. Overlooking some of the essential factors or lack of knowledge can impact the throughput and business outcomes. Therefore, we propose an end-to-end automated decision support system with explanation for business processes. The system uses the proposed process-aware feature engineering methodology that extracts features from process and business data attributes. The system helps a decision-maker to make quick and quality decisions by predicting the decision and providing an explanation of the factors which led to the prediction. We provide offline and online training methods robust to data drift that can also incorporate user feedback. The system also support predictions with live instance data i.e., allow decision-makers to conduct trials on current data instance by modifying its business data attribute values. We evaluate our system on real-world and synthetic datasets and benchmark the performance, achieving an average of 15% improvement over baselines.