A native of Los Angeles, Leighton studied conducting with Paul Salamunovich at Loyola Marymount University, where she earned her BA in choral music. She later obtained her MM in vocal performance and DMA in choral music from the University of Southern California.

A principal solo artist for more than two decades, Leighton has performed with many of the world's most eminent conductors, including Pierre Boulez, Zubin Mehta, Lorin Maazel, Simon Rattle, Esa-Pekka Salonen, Gustavo Dudamel, Bramwell Tovey, and the late Rafael Fruhbeck de Burgos. Her opera credits include principal appearances with New York City Opera, Los Angeles Opera, Glimmerglass Opera, Cologne Opera, Paris Opera and Glyndebourne, and her voice can be heard on more than 45 major film soundtracks, including the Disney animated feature, Frozen; Godzilla; and providing many of the vocal sound effects for the upcoming Transformers 4: Age of Extinction.

As a choral conductor, Leighton embraces a broad range of music, from the Renaissance to the Romantic Era, although she is particularly dedicated to twentieth and twenty-first century compositions. A long-time advocate of music education, she inaugurated Los Robles Master Chorale's annual High School Choral Festival, launched the High School Choral Leadership Workshop, and has established LRMC's Young Artist Choral Composers Competition.

Leighton was named the first Associate Conductor in the history of Los Angeles Master Chorale in July 2011 following a year as Assistant Conductor. She was appointed Artistic Director of Los Robles Master Chorale in 2008, and Music Director of New West Symphony Chorus in 2009. She was appointed Interim Director of Choral Activities at La Sierra University in May of 2013, where she taught two choirs and conducting until June of 2014. In addition, she regularly conducts the Los Angeles Master Chorale Chamber Singers, and has also been guest conductor for El Dorado Opera, Santa Clara Chorale and the Santa Monica Summer Music Series. Leighton has prepared choirs for Gustavo Dudamel, Esa-Pekka Salonen, the late Rafael Fruuhbeck de Burgos, Bramwell Tovey, Leonard Slatkin, Michael Tilson Thomas, Boris Brott and Marcello Lehninger.

In addition to a variety of appearances as a choral conductor with Los Angeles Master Chorale, Los Robles Master Chorale, New West Symphony Chorus, El Dorado Opera, and La Sierra University Chamber Singers, Leighton also returned to the stage as a soprano soloist for the Verdi Requiem with the New West Symphony in March of 2014. This summer she will prepare Cavalleria Rusticana/Pagliacci in addition to preparing the premiere of Gustavo Dudamel's work Libertador, for Dudamel at the Hollywood Bowl.