While the name is most often associated with a 5.4% abv amber lager which had become very popular, it was originally marketed by Coors (DBA Unibev Ltd.) as a 4.9% red ale, George Killian's Irish Red: Red Ale.
Although commonly known for its amber lager at 5.4%, the brand was originally promoted as a red ale called "George Killian's Irish Red: Red Ale" with a lower alcohol content of 4.9%.