Irish singer-songwriter Dermot Kennedy’s timely puree of folky songwriting and moody beats has racked up millions of streams, a devoted audience and a No 1 debut album. Pinballing from viral buzz to fully-fledged chart sensation can lead to a slapdash live show, as artists struggle to scale up their music. But, in an ambitious evening in which London’s Hammersmith Apollo is packed to its scalloped rafters, Kennedy neatly sidesteps any teething troubles.

Tonight his music gains an impressive sense of scale, with a three-piece band framed by intertwining tree trunks and a giant video screen showing abstract images (swooping birds, the white of an eye). Yet Kennedy’s versatile voice is the real draw. At times, it could soundtrack a Netflix weepie; at others, he sounds like a grizzled sailor. The hip-hop/indie hybrid Outnumbered is speeded up, its rapped verses sharpened, while acoustic mea culpa For Island Fires and Family is played to pin-drop silence.

Kennedy deftly blends stagey moments with intimacy on the gospel-inspired Glory: the stage is drenched in red light and dry ice, recalling Bat Out of Hell: The Musical. Yet he quickly snuffs out theatrics for a touching singalong. For the devoted ballad After Rain, fans pull out paper sleeves, transforming their phone lights to coloured lanterns.

He brings an of-the-moment dynamism to Radio 2-friendly balladry, but the formula of hushed verses and booming choruses begins to wear. Big slots seem within reach, even if his current range of material might not fully compel a casual audience.

• Touring the UK until 19 December.