Louise Johnson began her harp studies at the Sydney Conservatorium of Music High School, and later studied at the Cleveland Institute of Music and Salzedo Summer Harp School in the United States with Alice Chalifoux.
At 18, she was appointed Principal Harp of the Queensland Symphony Orchestra, a position she held for one year before continuing her freelance career overseas. She lived in London between 1983 and 1985, performing with the London Symphony Orchestra as Guest Principal Harp and Second Harp under the baton of Claudio Abbado and Richard Hickox. She also gave recitals in Wigmore Hall and the Purcell Room.
Louise Johnson has performed with all the major Australian symphony and opera and ballet Orchestras, the Australian Chamber Orchestra and the Australia Ensemble. She also performed with artists such as Cher, Sammy Davis Jnr and the Bee Gees, and has toured Australia with companies such as the Bolshoi and Sadler's Wells ballet. She has also played for the Bolshoi Opera and with Luciano Berio, in a concert of his own works.
Having given her first performance with the Sydney Symphony Orchestra at the age of 14, she later joined the orchestra as a permanent member, and was appointed Principal Harp in 1985.
She regularly appears as a soloist with the SSO. In 1990 she performed the Mozart Flute and Harp Concerto with James Galway and in 2006 she performed Spohr's Concertante for Violin and Harp with Michael Dauth. In 1996 she performed the Ginastera Harp Concerto in Seattle for the World Harp Congress.
Louise Johnson has taught harp at the Sydney Conservatorium for 24 years. She is in demand as a tutor and teaches regularly at the Australian National Music Camp.