Joanna has been a leading actress in the West End and on the international stage; as Kim in Miss Saigon (London, original Australian production, original United Kingdom & Southern Ireland Tour), Eponine & Fantine in Les Miserables (London & Windsor performed for HM Queen Elizabeth II and the Royal Family), Mary Magdalene in the 1996 revival of Jesus Christ Superstar (London), Mimi in Rent (European Tour), Christmas Eve in Avenue Q (London), Sheila Franklin in Hair (London), Thanh in the world premiere of The Real Love (Los Angeles), Heidi in I Sing! (London), The ingénue June in Musical of Musicals (London), Francesca in the international premiere of The Bridges of Madison County (Manila), Inang Bayan in Rebel EDSA 30 (Manila), Maria in West Side Story (Manila), Maria Von Trapp in The Sound of Music (Manila), Nellie Forbush in South Pacific in Concert (Manila), Blue Fairy in Pinnochio: A New Musical (Singapore), West End Women (UK Tour), Defying Gravity: The Songs of Stephen Schwartz (Sydney), Grizabella in Cats (UK and European Tour 2013-14, World Tour 2017-2018) and Jenna in the International Premiere of Waitress (Manila).
She can be heard on the cast recordings of Miss Saigon: Complete Symphonic Recording as Kim, Jesus Christ Superstar: 1996 London Cast as Mary Magdalene, The Postman and the Poet as Beatriz Gonzalez and the soundtrack of the feature film Ang Larawan as Candida. Her debut album Joanna Ampil was recorded in Abbey Road Studios in 2007 by JAY Records, followed by Try Love in 2010 by Sony Music and Joanna Ampil in 2014 with VIVA Records. Her latest singles are Always Better & Memory.
She portrayed Candida in the feature film Ang Larawan (A Portrait of the Artist as Filipino) directed by Loy Arcenas in 2017 where she won the Metro Manila Film Festival MMFF 2017, PMPC Star Awards, Gawad Pasado, Luna, Gawad Tangi, Guillermo Award, Urduja Best Heritage Film Awards and the prestigious Gawad Urian Best Actress Awards.
Joanna finished filming the digital series Babae Sa Septic Tank 3 with Eugene Domingo, directed by Marlon Rivera premiering in July 2019; and Call Me Tita directed by Andoy Ranay in August 2019 for iWant TV (ABS_CBN, Dreamscape and Heaven's Best Entertainment) .
She will be reprising the roles of Mary Magdalene in Jesus Christ Superstar in Tokyu Theatre Orb (Tokyo) in October 2019 alongside Declan Bennet, Ramin Karimloo and Telly Leung; and Grizabella in Andrew Lloyd Webber's Cats the musical for the International Tour starting November 2019.