Luke Robert Hemmings (born 16 July 1996) is an Australian singer and musician, best known for being the lead vocalist, rhythm guitarist, and a founding member of the pop rock band 5 Seconds of Summer. Since 2014, 5 Seconds of Summer have sold more than 10 million albums, sold over two million concert tickets worldwide, and the band's songs streams surpass 7 billion, making them one of the most successful Australian musical exports in history.^[1][2][3][4]

His debut studio album, When Facing the Things We Turn Away From, was released through Sony Music Australia on 13 August 2021. When Facing the Things We Turn Away From debuted atop the ARIA Albums Chart and peaked within the top 20 in Belgium and the United Kingdom.^[5]

Hemmings was born on 16 July 1996, and raised in the Freemans Reach suburb of the Hawkesbury district in New South Wales.^[6] His father—Andrew Hemmings—was previously employed as a maintenance worker, while his mother—Liz Hemmings (née Pascoe)— is a former accountant turned high school mathematics teacher, now working in photography.^[7][8] Hemmings has two older brothers: Ben and Jack, both who previously worked as builders, with the latter now owning a street-wear clothing label.^[9][10] Hemmings has spoken on his working-class upbringing; elaborating: "[The band's] beginnings were so humble. [...] I grew up in a small house in the middle of nowhere".^[7] When he was 10 years old, Hemmings' brothers taught him how to play guitar, later prompting him to take professional lessons and learning from YouTube tutorial videos to learn how to play the instrument.^[6] Eventually, Hemmings began busking throughout his later childhood.^[11]

In Year 7, Hemmings switched schools, attending Norwest Christian College, where he met future band-mates, Calum Hood and Michael Clifford, later revealing that he initially disliked and was "enemies" with Clifford.^[12] Hemmings eventually befriended Hood after they performed a Secondhand Serenade cover at a school talent show, and later befriended Clifford after learning they had similar music taste.^[6] Following the band's rise to fame, Hemmings continued with his high school education, opting to switch to distance learning. In 2013, he chose to not finish Year 12, the final year of secondary schooling in Australia, due to his commitment to the band.^[13][14]

In 2015, Hemmings began an on-again, off-again relationship with social media influencer Arzaylea Rodriguez.^[28][29] The couple ended their relationship in May 2017.^[30]

On 8 June 2021, Hemmings posted on his Instagram account announcing his engagement to his girlfriend of three years, Sierra Deaton.^[31] The couple currently live together in Los Angeles.^[32] He confirmed the two are married at the 81st Golden Globe Awards.^[33]

As of 2020, Hemmings' net worth is estimated to be US$20 million.^[34]