After making the difficult decision to leave Mighty Morphin Power Rangers, Johnson bounced around in a few TV movies before auditioning for The WB drama Felicity in 1998. According to Johnson, she landed the role of Julie Emrick, a singer/songwriter who quickly becomes the best friend to Keri Russell's Felicity, after show-creator J.J. Abrams spotted her heading for the bathroom. Which sounds creepy to us, but that's Hollywood, right? "J.J. told me that when I walked by the room to go to the bathroom, and they saw me while they were auditioning people for Julie... Before I even came into the room, he's like, 'Oh! There she is. There's Julie.' Like, he already knew. He saw me and he's like, "There she is." So I thought that was kind of cool."

Despite being one of the original cast members, Johnson would eventually leave Felicity after just two seasons. At the time, Abrams would tell TV Guide that he made a difficult decision to cut Johnson from the show. "I felt like in a weird way we were wasting Amy Jo's time. She's an incredibly gifted actress, but she wasn't getting enough stuff to do. I wish we had enough money and time to focus on all of the characters. But the way the stories were going, I thought it was more fair to let Amy Jo [go]." Clearly, there were no hard feelings between the former Power Rangers star and Abrams as Johnson was more than happy to return as Julie for the final four episodes of Felicity. However, her reasons were leaving the show would differ from the version Abrams told TV Guide.