"It was great to be with [my dance partner] Tristan [McManus] again and all my buds, all these lovely friends I made," she told PEOPLE after the show.
The 74-year-old, who was diagnosed with terminal brain cancer earlier this year, has defied the dire predictions that she only had months to live, and says she's been feeling "pretty good" since leaving the show in October.
"I had a few little strange things but they probably would have happened anyway," she said. "I don't have any big terrible symptoms, so as long as that's happening and I'm seeing my doctors, what's to complain about? There's people out there really suffering, so I'm feeling pretty good."
The Rhoda star said she wished she'd had a little more time to rehearse with McManus before they took to the dance floor one last time on Tuesday, but admitted that the reason she did the show was "to tell people to keep moving – even if you don't get the steps, keep on moving, one foot in front of the other, as best you can."
As she looks forward to celebrating the holidays with her family – something that she wasn't sure she'd live to see – Harper is savoring every day, telling PEOPLE, "I'm not looking back. I'm only looking forward."