Moya Brennan, who has died aged 73, was a founder member, lead singer and harpist with the Irish folk band Clannad. It was Moya’s ethereal singing voice that contributed to the band’s distinctive sound, particularly on the theme music for the television series Harry’s Game in 1982. Moya later pursued a successful solo career, collaborating and recording with an impressive number of performers across the musical spectrum.

Formed in 1970, the band was initially called Clann As Dobhar (the family from Dore), which was soon shortened to Clannad. The band members were all related: Moya’s brothers, Ciarán and Pól Brennan, were joined by Pádraig and Noel Duggan, identical twins who were Moya’s uncles, though very similar to her in age. For a time, Moya’s sister Enya was also a member, until she left to pursue her highly successful solo career.

In 1973, Clannad won a competition at the Letterkenny folk festival: their prize was a record deal with Philips Records. Their first, eponymous album received a mixed reception in Ireland because singing in Irish was, at the time, associated with poverty, although it was their normal, everyday language. This made them more determined to continue, finding new audiences in Europe and the US. Clannad 2 (1974) featured a synthesiser and folk-rock influences from groups such as Steeleye Span. This blend of the old songs, plus recently written material, mainly sung in Irish, in a contemporary style using harmonies and electronic sounds, upset the purists but attracted new audiences.

Clannad had already made six albums when they wrote the music for a Yorkshire Television programme set in Belfast during the Troubles. Theme from Harry’s Game was the result: released as a single, it reached No 2 in Ireland and No 5 in the UK, leading to an appearance on Top of the Pops, the show’s first song in Irish. The sound was created by multi-tracking Moya and Ciarán’s vocal harmonies, the layering sounding almost hymn-like. The ethereal sound contrasted with the violence of the programme’s storyline. The song was included on Clannad’s seventh studio album, Magical Ring (1983), and won an Ivor Novello award.

By then, Clannad were moving away from traditional Irish song, but the language and the rugged beauty of the Donegal landscape continued to be vital influences on the band’s music, with Moya’s haunting, mystical voice continuing to define their sound. After the success of Harry’s Game, Clannad were commissioned to write the music for ITV’s 26-episode series Robin of Sherwood, broadcast between 1984 and 1986. The music was released on the album Legend; they won a Bafta for best original television music. Their 1985 album Macalla featured In a Lifetime, with Moya duetting with Bono. In 1999 their Landmarks album won a Grammy for best new age album.

Moya was the eldest of the nine children of Máire (known as Baba, nee Duggan), a music teacher, and Leo Brennan, who both performed in an Irish showband, Slieve Foy Band, and also owned a pub, Leo’s Tavern, where Clannad made their debut. The family grew up in Gweedore in the Gaeltacht, the Irish-speaking area of Donegal. Moya studied harp, piano and singing at the Royal Irish Academy of Music, Dublin.

Clannad stopped performing in 1999, but before then, Moya was pursuing a solo singing career. Her debut album, Máire (1992), was followed by Misty Eyed Adventures, Perfect Time and Whisper to the Wild Water, the last of which was nominated for a Grammy. In total, she released 15 solo albums, accompanied by the Moya Brennan Band. Moya’s daughter, Aisling Jarvis, joined the band in 2012.

By this stage, Moya had a deep Christian faith, which was reflected in her songwriting. In 2000, she performed her song Perfect Time at the World Youth Day in Rome in front of Pope John Paul II and more than two million people.

Moya collaborated on recordings with a large and diverse number of fellow performers. Folk artists such as Paul Brady, Dónal Lunny and the Chieftains, and rock and pop performers including Robert Plant, Chicane, Mick Jagger, Runrig, Shane MacGowan, Van Morrison and Ronan Keating all recorded with her.

In 2000, Moya wrote an autobiography, The Other Side of the Rainbow, in which she described her former addiction to alcohol and drugs and her resulting renewed Christian faith. She became a goodwill ambassador for Christian Blind Mission, travelling to the Democratic Republic of the Congo, Brazil and Belize. She also performed at fundraising concerts for the rehabilitation of those affected by drug and alcohol dependency.

With other singers and musicians, Moya recorded an album, Irish Women in Harmony (2020), for the domestic abuse charity Safe Ireland.

Clannad re-formed in 2008, the same year that their recording of Down by the Salley Gardens was used in a music GCSE listening paper. A new album, Nádúr (Nature), was released in 2013, and they embarked on an international tour. Following an anthology album in 2020, there was further touring, delayed by Covid-19. Pádraig had died in 2016, but after the death of Noel in 2022, touring ended in 2023, with a final concert at London’s Royal Albert Hall in October 2024.

Although Moya used her Irish name, Máire Ní Bhraonáin, she adopted the name Moya Brennan in 2002, Moya being the phonetic pronunciation of Máire. In 2009, she formalised the change by deed poll.

Her first marriage, in 1985, to the musician Pat Farrell, ended in divorce. She is survived by her second husband, the photographer Tim Jarvis, whom she married in 1990, and their two children, Aisling and Paul. In recent years, Moya had suffered with pulmonary fibrosis.