Despite receiving negative reviews from music critics, the song debuted at number one on the UK Singles Chart, and at number two in Ireland, becoming her biggest point to date in these countries. The Guardian chose the song as the best number one single of 2011.
"Swagger Jagger" received its first airplay on 20 June 2011. The single was leaked onto the internet on 15 June, but this version was later confirmed as only the demo of the track on Lloyd's Twitter account. Lloyd performed the song on T4 on the Beach and also performed at the Leeds Aire FM Party in the Park and Key 103 Live Manchester, both on the day of release of "Swagger Jagger".
The song has received mainly negative reviews from critics. Initial reviews compared the song to the Christmas carol "Little Donkey". However, in a positive review, Robert Copsey of Digital Spy gave the song four out of five stars writing, "Her debut single does little to change that, accusing her "haterz" of pilfering her wildly cherished swagger - the same people who are also looking, tweeting, youtubing and generally social media-baiting her. 'I can't stop, it's what I'm gon' be/ My swagger's in check,' she brattishly sing-speaks over a chunky schoolyard beat and squiggly club synths." He also noted similarities between the song's chorus and the American western folk ballad "Oh My Darling, Clementine". In the BBC's "Most Annoying of 2011", "Swagger Jagger" was voted the most annoying song of the entire year, an opinion shared by users at whosampled.com.
In a negative review, Sabotagetimes.com said of the track: "Coming across like a sink estate answer to the Black Eyed Peas, the track combines a shouty, tuneless verse with a chorus that riffs on ‘Oh My Darling Clementine’".
"Swagger Jagger" debuted at number one on the UK Singles Chart on 7 August 2011 ― for the week ending dated 13 August 2011. As of 16 December 2011, the singles sales has exceeded 200,000 copies in Britain. In Ireland, the single charted at number two on the Irish Singles Chart. The single debuted at number seventy nine on the Mega Top 100 in the Netherlands. After a performance during the finals of So You Think You Can Dance, the song re-entered the chart at number sixty.