O'Donovan began his career by posting animated shorts to Newgrounds under the name "RubberNinja". He would later establish a YouTube channel and begin uploading content there. His best known work was the series
Gamer Tonight, which was produced for the
ABC2 video game-based program
Good Game. The series featured a fictitious talk show whose host, voiced by frequent-collaborator
Arin Hanson, would interview various types of gamers. In August 2014, O'Donovan uploaded a video expressing his concerns with animation videos on YouTube. Discussing the changes made to YouTube's algorithms, he stated that the website was now accommodating live-action videos over animated videos due to the algorithm's emphasis on retention time and upload frequencies which would impede animation channels.
Game Grumps (bottom center), and Barry Kramer (top center) in 2015 In 2013, after
Jon Jafari's departure from the YouTube Let's Play series
Game Grumps, co-host Arin Hanson, launched a second show on the
Game Grumps platform. Originally conceptualized by O'Donovan, the show
Steam Train had O'Donovan joined by
Ninja Sex Party vocalist
Dan Avidan, where both would play
PC games (the title referencing online retailer
Steam). In June 2015, O'Donovan launched a 5-episode miniseries on the
Game Grumps channel called
Guild Grumps. O'Donovan mentored 4 members of the
Game Grumps crew in a 5-day race to advance from Level 90 to Level 100 in the
Warlords of Draenor expansion of
World of Warcraft.
After Game Grumps In 2020, O'Donovan left
Game Grumps on good terms, to prioritize making his own content. He has returned on multiple occasions as a guest and made a brief cameo in a video commemorating the series' 10th anniversary. His new YouTube channel,
RubberRoss, reached over 1 million subscribers in 2022. O'Donovan made a series of tweets criticizing the campaign, calling the practice "scummy as hell". The tweets, as well as additional statements from O'Donovan, were used in articles by
BBC,
Kotaku, and
PC Gamer while reporting on the issue. Since September 2021, O'Donovan's YouTube videos have primarily consisted of him and other artists collaborating within the online
Gartic Phone game. In January 2026, Australian studio
Glitch Productions announced that it partnered with O'Donovan and Arin Hanson for the release of
Gameoverse, a reboot of a 2009 webseries by O'Donovan. The
pilot episode is set to release in May on Glitch Productions's
YouTube channel. ==Personal life==