Flaherty was born in Pittsburgh, Pennsylvania. He began studying piano at the age of seven. When he was twelve he knew he wanted to write musicals and by age fourteen he had already composed his first musical score. He attended South Hills Catholic High School in Pittsburgh and later studied musical composition and piano at University of Cincinnati College-Conservatory of Music, graduating in 1982. He did additional graduate studies in Musical Theater at New York University.
As a college student, Flaherty played ragtime piano in a dance band. This early job would serve Flaherty well later in life when he had the opportunity to compose the score for the Broadway musical Ragtime.
He moved to New York City in 1982 and joined the BMI Lehman Engel Musical Theater Workshop, founded by music director Lehman Engel, where he met Lynn Ahrens, who was to become his longtime collaborator. He also studied Musical Theater in the graduate program at New York University during this time, where his teachers included Richard Maltby, Jr. and Arthur Laurents, among others. The first Ahrens and Flaherty collaboration that was produced was a children's show, The Emperor's New Clothes, for TheatreWorks USA in 1985. Their next produced musical was Lucky Stiff produced Off-Broadway in 1989, and their first Broadway musical was Once on This Island in 1990. In 1992, Flaherty and Ahrens were signed by Disney to write Song of the Sea, a coming of age story about a whale. Flaherty has since written many more full-length musicals, mostly in collaboration with Ms. Ahrens, all of which have been produced. The critically acclaimed revival of Ragtime ran on Broadway in 2009.
His and Frank Galati's musical about Gertrude Stein, Loving Repeating: A Musical of Gertrude Stein, opened on January 21, 2011 at International City Theatre, Long Beach Performing Arts Center, California. This "chamber-scale musical," premiered in Chicago in 2006, in a co-production of About Face Theatre and the Museum of Contemporary Art. The musical was initially titled A Long Gay Book, and had its premiere at Northwestern University in May 2003.
Flaherty also writes for film and the concert hall. He was nominated for two Academy Awards and two Golden Globe Awards for his first film, Twentieth Century Fox's animated Anastasia (1997). He also scored and wrote the songs for its animated sequel, Bartok The Magnificent. He wrote the original film score for the documentary After the Storm, which follows a group of teenagers as they perform Ahrens and Flaherty's Once On This Island in New Orleans post-Hurricane Katrina.
For the concert hall Flaherty wrote the music for the "American River Suite", with lyrics by Bill Schermerhorn and commissioned by Macy's. The piece was premiered in April 2009 at Carnegie Hall by the New York Pops and sung by Idina Menzel, Anika Noni Rose, and the children’s chorus from the Choir Academy of Harlem. It was broadcast nationally on the Fourth of July of that same year.
Flaherty and Ahrens have written a dance musical, Little Dancer, with direction and choreography by Susan Stroman, Inspired by the famous sculpture "Little Dancer, Age 14" by Edgar Degas, the musical had a reading in 2010 at Lincoln Center Theater and a developmental lab production in June 2012. Little Dancer premiered at the Kennedy Center, Eisenhower Theater in October 2014 and closed on November 30, 2014. The cast included Rebecca Luker, Boyd Gaines and Tiler Peck. The musical is "nspired by true events,[and] focuses on the relationship between a young ballerina and 19th century French painter and sculptor Edgar Degas" Much of the action is set in the Paris Opera Ballet.
Ahrens and Flaherty teamed up again to write a musical version of the film Rocky, titled Rocky the Musical. The show premiered in Hamburg, Germany in October 2012. The musical has a book by Thomas Meehan. Rocky the Musical premiered on Broadway at the Winter Garden Theatre on February 11, 2014 (previews), officially opening on March 13, 2014. The musical is directed by Alex Timbers, with boxing choreography by Steven Hoggett and choreography by Kelly Devine. The former occupant of the Winter Garden Theatre, the musical Mamma Mia!, transferred to the Broadhurst Theatre in late 2013.
He wrote the music for a new "dance-theatre musical", In Your Arms, which premiered at the Old Globe Theatre, San Diego, California, on September 16, 2015 in previews, officially on September 24. The show consists of 10 vignettes, written by Douglas Carter Beane, Nilo Cruz, Christopher Durang, Carrie Fisher, David Henry Hwang, Rajiv Joseph, Terrence McNally, Marsha Norman, Lynn Nottage and Alfred Uhry. Lynn Ahrens wrote the lyrics for the title song. Directed and choreographed by Christopher Gattelli, the show starred Donna McKechnie and George Chakiris. The musical had a staged workshop at the 2014 New York Stage and Film & Vassar's Powerhouse Theater at Vassar College.
He has received several commissions from Carnegie Hall, the Guggenheim Museum and the Boston Pops Orchestra, among others.
Flaherty married Trevor Hardwick on October 26, 2016 in New York City.
Lucky Stiff (1988)
Once on This Island (1990)
My Favorite Year (1993)
Ragtime (1998; Broadway revival 2009)
Seussical (2000; revival 2007)
A Man of No Importance (2002)
A Long Gay Book (2003), an early version of Loving Repeating
Dessa Rose (2005)
Loving Repeating (2006)
Chita Rivera: The Dancer's Life (2005), music also by others
The Glorious Ones (2007)
Rocky the Musical (2012)
Little Dancer (2014)
Anastasia (2016), stage version of film
"I Eat", contribution to The Seven Deadly Sins: A Song Cycle for Audra McDonald, performed on June 2, 2004
Bartok the Magnificent (1999)
After the Storm (2009)