Lisa Anne Haapaniemi was born in Houston, Texas, the only daughter of six children born to Edmond Haapaniemi, then Director of Water Safety Services at the Red Cross, and registered nurse Karin Haapaniemi Niemi has said her Father and her mother's profession were her inspiration and encouragement. She graduated from the Houston Ballet Dance Company in 1974. She shortened her surname from Haapaniemi to Niemi in 1977 for her theatre stage name.

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 15 years old. Niemi and Swayze were married on June 12, 1975 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.

In 1985, Niemi Swayze began living on a 5-acre (20,000 m) homestead near the Angeles National Forest, along with a "menagerie of dogs, prized Arabian horses and rodeo cattle." She also had a 20,000-acre (81 km) ranch in New Mexico.

She co-starred in Steel Dawn (1987) with Swayze and co-starred in Beat Angel (2004). Niemi also appeared in Letters from a Killer, Next of Kin, Younger and Younger, Live! From Death Row, She's Having a Baby and Slam Dance. Patsy Swayze choreographed the films Urban Cowboy and Grandview, U.S.A. Niemi directed Dance, a 1990 film.

Niemi Swayze wrote, directed and starred in the 2003 film One Last Dance alongside Swayze. One Last Dance was based on Without a Word, a successful play written 18 years before which had won six Drama Critics Awards. Niemi said, "It was basically based on our experiences as concert Dancers in New York, and it affected people a lot."

On September 29, 2009, Niemi Swayze released a memoir, The Time of My Life (ISBN 9781439158586), which became a New York Times Best Seller, and had been co-written by Patrick Swayze, and was finished just shortly before his death. On January 2, 2012, Niemi Swayze released her New York Times Best Selling memoir, "Worth Fighting For."

She is a licensed pilot and flew Swayze to his cancer treatments prior to his death. While filming One Last Dance in Winnipeg, Manitoba, Niemi was made an honorary citizen of the Canadian city. After her husband's death, she became the Chief Ambassador of Hope for Pancreatic Cancer Action Network. In July 2011, she was honored with the title of dame and invested in the Royal Order of Francis I.

On December 28, 2013, it was announced that she was engaged to Albert DePrisco, a jeweller. On May 25, 2014, the couple were married.