Although the Problem-Based Learning (PBL) approach has been explored in diverse academic disciplines and has proven to have an impact on both learning outcomes and other academic-related life skills, such as problem-solving and critical thinking, very few studies have been conducted in language courses, let alone among English as a Foreign Language (EFL) learners. In view of this, and with Social Constructivist Theory in mind, the researchers of this study redesigned the curriculum of an English Business Communication course in order to create a more genuine and interactive learner-centered environment, with the goal of fostering critical thinking and problem solving skills. In the study, 51 English-majored juniors at a four-year comprehensive university in Central Taiwan engaged actively in team-based discussion of business-related scenarios/cases to grapple with problems and find solutions. The participants were divided into nine groups, with each consisting of six to seven members, and each was assigned one professionally-trained tutor. They were required to tackle two real-life case studies with each case spanning three weeks. Each member in the group was assigned a major individual duty as well as collective responsibility to work in both online and physical classroom environments. The quantitative findings of pre- and post-surveys revealed that social interaction and problem solving skills did improve significantly as a result of this PBL instruction. Qualitative findings also found that learners preferred learning via active discussion and interaction with their peers to learning via traditional teacher-centered lecture-based instruction. Detailed descriptions on the curriculum design and the implementation of the study are also provided as a guideline for language instructors who wish to re-design the curriculum for their future language courses.