UK website Digital Spy gave the song three stars out of five and commented that: "[Morning Sun] is a bit like something from mid-'90s Britpoppers Electrasy - a straightforward trad-rock song complete with metronomic piano chords, swooning strings and the rest. Two minutes in, it gets close enough to 'I Am the Walrus' for George Martin to consider giving his lawyer a bell. Sure, it's not the most adventurous release of Williams's career, but it's pleasant to its bones and the lyrics have just enough about them to avoid the trap of self-regarding introspection that marred the likes of 'Strong' and 'Come Undone' in the past."
Williams performed the song on 23 January 2010 at the NRJ Music Awards where he also received two awards for International Male Artist of the Year and the NRJ Award of Honour. "Morning Sun" was performed on 13 February 2010 (Williams' 36th birthday) on the UK TV show So You Think You Can Dance. The song was also performed as part of a greatest hits medley at the 2010 BRIT Awards where Williams won the prestigious Outstanding Contribution to Music Award on 16 February. "Morning Sun" was performed by Williams at the 2010 Echo Awards in Berlin on 4 March, where he won the award for Best International Male Artist. He performed the single yet again on appeal night for Sport Relief 2010.