At age 14, at the Houston Ballet Dance Company, Niemi met the owner and director's son, Patrick Swayze; the two eventually began dating when she was 19 years old. Niemi and Swayze were married on June 12, 1975 and remained married until Swayze's death from pancreatic cancer on September 14, 2009. Shortly after they wed, the couple moved to New York City to pursue their dance careers until the late 1970s, when they relocated to Los Angeles, California. In addition to dancing and filmmaking, they ran a construction business and raised horses together. The Swayzes had no children.