Before 1990 he worked in the Bank of Ireland for twelve years, and occasionally performed in local bands. He was among the most prolific and successful composers in contemporary Irish film and television. Centered in Dublin, his TV work included commissions for the title music for RTÉ Irish National Television Network News, and the original score for the natural history series Waterways, as well as a number of commercial spots for Guinness products and the Irish National Lottery. In motion pictures, Hardiman earned acclaim for his score to the 1996 feature My Friend Joe, which garnered the Crystal Bear for Best Children's Film at the Berlin Film Festival. Also in 1996, Hardiman was contacted by Flatley, with the resulting soundtrack to Lord of the Dance becoming an international hit; the composer's debut solo album, Solas, followed in 1998, and a year later he resurfaced with Feet of Flames. His 2000 release, Anthem, blended the Celtic sounds that he was famous for with more pop influences. The track "Ancient Lands" from Anthem was used by the 2002 Olympic men's figure skating champion, Alexei Yagudin, in his program "Overcome".