Since then, he has been credited on the singles "Life Is a Rollercoaster" and "Lovin' Each Day" by Ronan Keating, "Inner Smile" by Texas, "Murder on the Dancefloor" and "Mixed Up World" by Sophie Ellis-Bextor, all of which were commercial successes in the early 2000s.
At age 14, he joined a band, The Circus, with his older brother, Stephen Aiuto, and classmates George Snow and John Mabarak.
"[2] Since the summer of 1999, Alexander has written and produced hit songs for several artists, including Brisebois, Enrique Iglesias, Texas, Geri Halliwell, S Club 7, Melanie C, Rod Stewart, Hanson, Sophie Ellis-Bextor, Mónica Naranjo, and Ronan Keating (he co-produced and co-wrote the album Destination).
[1] Alexander's composition "The Game of Love", recorded by Santana and Michelle Branch, earned him a Best Pop Collaboration prize at the 45th Annual Grammy Awards.
[1] AllMusic's Stephen Thomas Erlewine described Alexander as "the catchiest, smartest professional mainstream pop songwriter of the early 2000s.
[6] "Why Can't We Make Things Work", written by Alexander (and Rick Nowels), was released by Any Dream Will Do winner Lee Mead on his self-titled album in November 2007.
On November 4, 2014, Alexander appeared and performed publicly for the first time in 15 years at the Hollywood Music in Media Awards, singing "Lost Stars.
"[8] Since 2018, Alexander has been involved in writing sessions with Phil Thornalley and his 1970's singer-songwriter inspired music project, Astral Drive.
In January 2024, Sophie Ellis-Bextor's "Murder on the Dancefloor", co-written by Alexander, became a viral hit due to its appearance in the film Saltburn.