Nicholas Francis Earls was born in Northern Ireland on 8 October 1963 and moved to Australia with his family in 1972. He was educated at the Church of England Grammar School and graduated from the University of Queensland in 1986 with a Bachelor of Medicine and Bachelor of Surgery (Honours). During the late 1980s and early 1990s, he worked in general practice, hospitals and for an insurance company while building his writing career. Earls published a book of poems in 1985 and a collection of short stories in 1992, but he gained wider recognition with the publication of Zigzag Street and the young adult novel After January in 1996. He won several awards for these works and has since pursued a career writing fiction for both adults and young adults.

His young adult novel 48 shades of brown (1999) received further accolades, and he has developed a strong following with adult novels Bachelor kisses (1998) and Perfect skin (2000). Known for the comedic elements in his fiction, Earls has performed some of his works at festivals, and several have been adapted for the stage. He has also written plays performed in Australia and England, as well as jingles, comedy scripts, and corporate videos. Beyond writing, Earls has been actively involved in charitable work and has contributed to promoting his home city of Brisbane. In 2006, he was named Queensland's Multicultural Champion in recognition of his 'energetic and passionate advocacy for the rights of refugees and the disadvantaged' and was also awarded the University of Queensland's 2006 Alumnus of the Year.