The singer, whose real name is Dominic Harrison, was attending the demonstration in Santa Monica with his ex, fellow pop star Halsey, when trouble flared.
Dressed in a black boiler suit, the star was seen treating fellow protestors while wearing disposable gloves, as Yungblud helped.
She later shared her experience from being at demonstrations on Twitter and called for more medics on the ground, while claiming protestors were ‘shot at, gassed and antagonised’.
In a series of tweets, Halsey clarified that she hadn’t been arrested and had been offering medical assistance, treating injuries she was ‘not qualified’ to at the demonstration.
The pair were pictured tending to wounded protestors with Halsey tweeting: ‘And a big personal thank you to @yungblud who literally ran exposed in front of rounds being shot to drag wounded people to safety without even thinking twice.’
Yungblud did the same, calling Halsey ‘incredible’ for treating those that were wounded.
He tweeted: ‘i need to say @halsey u were incredible today. u acted fearlessly and selflessly. u were so brave and inspirational. when innocent people were unlawfully wounded, u were there with a medical kit bandaging them up. u didn’t think about yourself for one moment. i am proud to know u.’
The pair previously dated, but split last year in September.
Born in Doncaster, his dad Justin was an antique guitar dealer and ran Doncaster’s much-missed Music Ground guitar shop in Hall Gate for many years.
The shop attracted the likes of Noel Gallagher and The Smiths’ Johnny Marr as well as Canadian rocker Bryan Adams during its heyday.
His grandad Rick also played with glam rock legends T-Rex in the 1970s.
His own musical career has seen him perform at the Leeds and Reading Festival as well as a string of sold out tour dates across the world and success with his debut album 21st Century Liability.