On 19 May 2006, he signed up to the online video-sharing website YouTube and in December 2008 uploaded his very first video of him singing "Breathe", by fellow British musician Lee Carr.

[7] In 2006, Maynard starred as a young annoying Casper Rose in the Sky 1 television series Dream Team.

[9] He released the music video for his debut single "Can't Say No" on 1 March 2012,[10] which by September 2012 had already surpassed fourteen million views.

The single was met with positive reviews, with Lewis Corner (of Digital Spy) describing it as "playful, fun and immediately leaves you wanting another go",[11] while others compared Maynard to singer Justin Bieber.

Maynard largely disputed this comparison, stating "I'm not like Justin Bieber", but allowed that both gained popularity from being young and from being found through YouTube.

[16] On 9 June 2012, Maynard performed "Can't Say No" at the Capital Summertime Ball[17] in front of an 80,000 strong crowd.

[18] In November 2011, Maynard received a nomination for MTV's Brand New for 2012 award, competing alongside Delilah, Michael Kiwanuka, Lana Del Rey, and Lianne La Havas.

He collaborated with the likes of fellow pop stars Melanie C, Eliza Doolittle, Emma Bunton, Katy B, Kimberley Walsh, and Pixie Lott, on "Greatest Day", a track originally performed by a British band, Take That.

The track also featured past footballers such as Gary Lineker, Michael Owen, Geoff Hurst, David Seaman, Peter Shilton, Glenn Hoddle, and Dion Dublin on backing vocals.

Maynard also featured on a track called "Catch Me Here" by Drumsound and Bassline Smith which Conor had already written for 2 years.

In November 2018, Maynard began starring in the Broadway production of Kinky Boots at the Al Hirschfeld Theatre in the lead role of Charlie Price and gave his final performance on 10 January 2019.

[35] On 24 May 2024, Swedish singer songwriter Darin released the single "Moonlight"; Maynard is credited as a co-writer of the song.