Born in Auckland, Don McGlashan played French horn and percussion in the Auckland Symphonia from 1979 to 1982. He was a member of From Scratch from 1979 to 1986, as well as Blam Blam Blam's drummer and singer from 1980 to 1982. His song Don't Fight it, Marsha, It's Bigger Than Both Of Us was named Song of the Year in the 1982 at the New Zealand Recording Industry Awards.

After a year in New York as a member of Laura Dean Dancers and Musicians, he returned to New Zealand and founded The Front Lawn with Harry Sinclair. Combining theatre, song, dance, and film, the group toured extensively in Australasia, Europe, and America from 1985-90, picking up numerous awards. Together with Sinclair, and a group of Auckland performers, McGlashan co-founded Auckland's Watershed Theatre in 1990, and was heavily involved in the developing and programming of the venue in its early years.

From 1991, he was singer and main songwriter for The Mutton Birds, releasing four NZ top-ten albums and two top-five singles, including one No. 1 hit. His song Anchor Me won the APRA Silver Scroll in 1994. In 1995, the group signed to Virgin Records UK. Based in London until 1999, the band toured all over the world. Their third album, Envy Of Angels (1997), made the UK Sunday Times Ten Best Records of the Year list. McGlashan also writes music for film and TV, including the score for Jane Campion's An Angel At My Table (1990).

He composed and arranged fan-fares and pieces for the 1990 Commonwealth Games, and wrote a piece for orchestra, choir and soprano (Kiri Te Kanawa) for the 1993 New Zealand Expo pavilion in Seville. Since returning to New Zealand in 1999, McGlashan has been Musical Director of Auckland City's Millennium celebrations, and has written the score for the TVdrama series Street Legal, while also working on songs for a solo album and other commissions. In 2001, he was awarded the Auckland University Literary Fellowship for his song writing.

Don McGlashan performs at the Arts Foundation Icon Awards, Wellington, 2005

Don McGlashan maintains a busy performance schedule both as a solo artist and with his new band Don McGlashan and the Seven Sisters, comprising SJD on bass, pedalsteel guitarist John Segovia (Boxcar Guitars) and drummer Chris O'Connor. Highlights include writing the original score to Toa Fraser's feature film No. 2, which won the audience award in its category at the Sundance Film Festival in 2006; Two of Don's songs made waves for other people: Anchor Me, which enjoyed renewed chart success as the Rainbow Warrior tribute, performed by a diverse group of young New Zealand artists including Che Fu, Anika Moa, Milan Borich and Kirsten Morelle; and Bathe In The River, written for No. 2 and performed by Hollie Smith. His album Warm Hand was released in May 2006, on Arch Hill Records.

Don McGlashan performs at the Arts Foundation Laureate Awards, Auckland 2009

In 2002 Don received an Arts Foundation Laureate Award. In 2007 he received a Living Legend Award from the Auckland City Council and in 2011 he was announced as one of the recipients of the 2012 Distinguished Alumni Awards from the University of Auckland.