This study examined the effectiveness of a career course designed to increase career self-efficacy and exploration among undergraduate students from a university in Taiwan. A quasi-experimental study was conducted to compare a group of students who completed high-intensity action-based assignments (experimental group, n = 74) with another group that was assigned low-intensity action-based assignments (n = 197). Both groups answered the questionnaires in the first and eighteenth weeks of the course. Repeated measure analyses were conducted to examine the differences between the responses of both groups before and after taking the course. The results indicated that the career course could improve the students' career self-efficacy (t = -12.4, p < 0.001) and exploration (t = -15.1, p < 0.001). Although the results confirmed that high-intensity action-based assignments could enhance students' career exploration (t = -2.62, p < 0.01), neither group showed any improvement in terms of career self-efficacy. The control group exhibited higher career self-efficacy after attending the course than did the experimental group (t = 2.74, p < 0.01). The implications and scope for further research are also discussed.