Current online learning approaches are sometimes criticized for a "one-size-fits-all" approach and insufficient feedback, which may result in low levels of satisfaction and high dropout rates. To mitigate these shortcomings, we implemented a set of principles for designing personalized motivational feedback based on students' achievement goals. A sequential explanatory mixed-methods design was used to collect data. The results indicated students who received this feedback demonstrated significantly higher levels of motivation and satisfaction. However, their performance scores were not significantly higher than students in the control group. Post-interviews showed this personalized feedback helped students regulate their learning goals and behaviors and thus improved their learning. The evidence suggests this personalized feedback may benefit learning by improving motivation. While its effect on performance outcomes was not significant, we speculate that more complex factors may have obscured any performance effect.