The ZM network as it is today was founded in the early 1970s as three separate commercial music stations owned by Radio New Zealand in Auckland, Wellington and Christchurch. The name is derived from the former callsigns of the stations: 1ZM, 2ZM and 3ZM. Z denoted a Radio New Zealand commercial station and M stood for Music. The stations were carved off to The Radio Network (now merged into New Zealand Media and Entertainment) in 1996, and ZM spread across the country, originally as three separate networks before finally merging to form one nationwide network in 2000.
The network's head office and main studios are based in Auckland, where all of the programming is produced.
The breakfast show is presented by Carl "Fletch" Fletcher, Vaughan Smith and Megan Sellers with producers Caitlin Marett, James Johnston and Anna Henvest. News and sport sourced from the NZME newsroom is heard on the hour, with weather being heard every 30 minutes, read out live by Henvest. Fletch, Vaughan and Megan have presented the breakfast show since 2014, previously this show was presented by Pauline 'Polly' Gillespie and Grant Kareama from Wellington between 2001 and 2014. The original networked breakfast show was presented by Marcus Lush.
The workday show is presented by Bel Crawford. On Fridays, Bel hosts the 'Friday Jams' show which plays old school R&B hits. The show proved to be so popular that ZM hosted a "Friday Jams Live" concert at Spark Arena on the 22nd of October 2017.
Past announcers to present this show have included Nicki Sunderland & Lana Coc-kroft (2000 - 2002), Jason Royal (2003), Aroha Hathaway (2003 - 2005), Sarah Gandy (2005 - 2009 + 2012 - 2014), Mark Dye (2009 - 2012), Reagan White (2014), PJ Harding (2014) and Amante Falkenstein (2015 - 2016).