McGuiness is vegetarian, although he has described himself as “not a militant vegetarian by any means”. He was named PETA’s Sexiest Male Vegetarian Celebrity in 2013. He can play the drums. He discovered The Wanted by Googling ‘auditions’ and getting two results, one for a circus and one for the band.

On 24 August 2015, McGuiness was confirmed as a celebrity contestant in the BBC’s Strictly Come Dancing. He was partnered with professional dancer Aliona Vilani. In the third week of competition, he was awarded a total of 37 points out of 40, the highest week 3 score in the history of the competition, for his jive. He also received the first 10 of the series. In week 6, he danced an American Smooth to “Li’l Red Riding Hood” by Sam the Sham and the Pharaohs and scored 34, putting him in second place by only one point. In week 10 he danced a tango to “When Doves Cry” by Prince and scored 38. In Week 11 he danced a rumba to “Falling Slowly”, from the musical Once, and scored 39, putting him at the top. In the semi-final his Charleston scored 37. In the final, on 19 December 2015, the couple danced a Quickstep to “My Generation” by The Who, scoring 36, a showdance to “Can’t Feel My Face” by The Weeknd, scoring 35, and a Pasodoble to “It’s My Life” by Bon Jovi, scoring 39. In the public vote the couple were voted the series winners, gaining the Glitterball trophy.

On 2 December 2017, McGuiness appeared on BBC’s Pointless Celebrities.

In October 2018 McGuiness appeared at the London Palladium in the show Rip it Up the 60s, alongside Harry Judd, Aston Merrygold and Louis Smith. The show then transferred to the Garrick Theatre.