Harket was named a Knight First Class of the Order of St. Olav by King Harald for his services to Norwegian music and his international success.

The son of Reidar, a chief physician at a hospital, and Henny, an economics teacher, and brother to Gunvald, Håkon, Ingunn and Kjetil, Morten grew up in Asker in southern Norway.

[3] His early musical influences included Uriah Heep,[4] Jimi Hendrix,[4] Queen, Johnny Cash, Simon and Garfunkel, David Bowie, and James Brown.

[5] The trio, comprising lead vocalist Harket, guitarist Paul Waaktaar-Savoy (Pål Waaktaar until his marriage in 1994), and keyboardist Magne Furuholmen, formed on 14 September 1982, and left Norway for London to make a career in the music business.

Ratcliff dealt with all the technical and musical aspects; Slater was the international business manager and liaison to Warner Brothers' head office.

In 1984, A-ha released their first single, "Take On Me", which became a hit only on the third attempt in 1985, after it had been re-recorded and accompanied by a music video directed by Steve Barron.

The single's international success helped A-ha's debut album Hunting High and Low to sell over 10 million copies worldwide.

Their eighth studio album Analogue was released in 2005, and became a big hit worldwide, achieving Platinum certification in the UK.

Subtitled as Summer Solstice, This live album was released that October, and the acoustic version of "Take On Me" was made part of the soundtrack of the Hollywood movie Deadpool 2.

"[10] On A-ha recordings, Morten has sung with Graham Nash, Lissie, Alison Moyet, Ian McCulloch, Ingrid Helene Håvik and Anneli Drecker.

[17] Harket has collaborated in live performances and in studio recordings with several artists, among them Pakistani rock band Junoon, on the songs "Piya" and "Pyar Hai Zindagi"; and Hayley Westenra, on "Children First".

He has also performed and worked with many other Scandinavian artists, such as Bjørn Eidsvåg, Silje Nergaard, Oslo Gospel Choir, Espen Lind, Elizabeth Norberg-Schulz and Carola Häggkvist.

[1] His voice is capable of "the greatest falsetto in the history of pop music EVER...", according to NME's Sylvia Patterson,[30] and of an "unyielding groan" as described in Entertainment Weekly.

[31] Sound engineer Gerry Kitchingham, who worked with A-ha on "Take On Me", described Harket as "an excellent singer" with "this incredibly strong falsetto and almost choir-boyish clarity".