Born to U2 frontman Bono and activist Ali Hewson in Dublin, he grew up in Killiney and featured on the cover of U2's Songs of Experience in 2017.

He formed Inhaler in late 2012 with two friends from St Andrew's College, Dublin, with a fourth member joining later, and released the albums It Won't Always Be Like This (2021) and Cuts and Bruises (2023) as part of the band.

[7] In late 2012,[9] while at St Andrew's College, he met Robert Keating and Ryan McMahon[10] and formed a band with them and a vocalist under the name "The Collapsible Chairs".

[8] In December 2017, a photograph taken by Anton Corbijn of Elijah holding hands with Sian Evans, the daughter of U2's the Edge, appeared on the cover of Songs of Experience, U2's fourteenth album.

[16] Hewson's parents made a point of not assisting further than necessary;[7] in an interview with Craig McLean of the Evening Standard in January 2023, he noted that after his Airbnb was cancelled on the band's first trip to London and he asked his mother to provide a hotel, he found himself instructed to sleep "on a park bench".

[22] Reviewing Inhaler in December 2019, BBC Culture remarked that Hewson's voice was "like you've got back in time, 40 years to witness [U2]'s first faltering steps in a sweaty, smoky Dublin club" [sic],[23] and while reviewing It Won't Always Be Like This for The Daily Telegraph, Neil McCormick found Hewson's "raw tone" reminiscent of Bono's, but with "a loose, understated fluidity to his melodies that is very pop contemporary".