Varela's first job was in 1995, playing Anette in Pony Trek, a children's film. Filming was in Iceland and Leonor was riding horses for three months. Then, referred to a French filmmaker by her dentist, she played in Shooting Stars (1997). Varela found her popularity on the rise at home when she was cast in the Chilean soap opera Tic Tac. After appearing in a few more television productions in the late 1990s, Varela was cast in a small role in The Man in the Iron Mask. In 1999, she played the title character in the TV movie Cleopatra. She fell in love with actor Billy Zane (Mark Antony) on the set, but they split up two years later. She has been married to philanthropist and musician Kevin Duane Taylor of Garland, Texas since April 13, 2008.

Roles in The Tailor of Panama and Texas Rangers (both in 2001) followed shortly thereafter, and as the fanged vampire princess in the action film Blade II. After that came Paraíso B and Pas Si Grave. Varela also had a short recurring role in the Fox Television series Arrested Development as the original Marta. She was nominated for the Ariel Award in 2005 in the category of Best Actress for Innocent Voices (2004). She also had a non-recurring role in Stargate: Atlantis.

Her latest projects are Americano, Caleuche: The Call of the Sea, Casas de Cartón and Gigola where she plays feminist Laure Charpentier. She played Jordana in Goal! 2. Jordana was a journalist who had a one-night stand with Santiago Munez (Kuno Becker). Varela is fluent in Spanish, English and French. She is also a marine life activist who is concerned with the welfare of whales. Leonor is also a vegetarian, which is how she thinks that her belly stays so flat and her skin so tight.

• Love and Virtue (2008) (in production) .... Morgana
• Caleuche: El llamado del mar (2008) (in production) .... Isabel Millalobos
• Deseo (2009) (post-production) .... Muchacha
  
• Balls Out: Gary the Tennis Coach (2009) (V) .... Norma Sanchez
  ... aka Balls Out: The Gary Houseman Story (International: English title)
• All Inclusive (2008) .... Miranda
• Hindsight (2008) .... Maria
• Hell Ride (2008) .... Nada
• Sleep Dealer (2008) .... Luz Martínez
• "Como ama una mujer" (2007) TV mini-series .... Sofia Marquez
• Where God Left His Shoes (2007) .... Angela Diaz
• Goal II: Living the Dream (2007) .... Jordana Garcia
• The Curse of King Tut's Tomb (2006) (TV) .... Dr. Azelia Barakat
• "E-Ring" .... Lt. Col. Cat Rodriguez (1 episode, 2005)
       - Pilot (2005) TV episode .... Lt. Col. Cat Rodriguez
• Americano (2005) .... Adela
• "Stargate: Atlantis" .... Chaya Sar (1 episode, 2004)
  ... aka Porte d'Atlantis, La (Canada: French title: dubbed version)
  ... aka Stargate: Atlantis (USA: Spanish title)
       - Sanctuary (2004) TV episode .... Chaya Sar
• Voces inocentes (2004) .... Kella
  ... aka Innocent Voices (International: English title)
• "Arrested Development" .... Marta Estrella (2 episodes, 2003)
       - Key Decisions (2003) TV episode .... Marta Estrella
       - Bringing Up Buster (2003) TV episode .... Marta Estrella
• Tais-toi! (2003) .... Katia/Sandra