The group was founded by three members of the Australian band the Frowning Clouds after that band broke up: guitarist and lead singer Zak Olsen, guitarist and bassist Daff Gravolin, and drummer Jamie Harmer. The three musicians lived not far from one another, and with some extra time on their hands, they began jamming regularly. Inspired by their youthful enthusiasm for hard rock and early metal bands such as Black Sabbath and Blue Öyster Cult, they started writing tunes that drew tongue-in-cheek inspiration from doom rock and psychedelia as well as hard rock. The longer they crafted heavy jams, the more they came to appreciate the style, and the less they approached the music with a smirk. In January 2015, ORB released their debut recording, a five-song cassette titled Womb. Within a few months, the group had earned a solid reputation among Australian heavy rock fans, and they struck a record deal with Flightless Records, the label founded by King Gizzard & the Lizard Wizard. ORB’s first vinyl release was a 7" single, “Migration” b/w “Migration 2,” that appeared in November 2015. Their first full-length album, Birth, was released in July 2016 by Flightless in Australia and by Castle Face in the United States and Canada. The album received positive reviews in the rock press, and in October 2017 ORB delivered their second LP, Naturality.