He is the rhythm guitarist, bandleader and principal songwriter of the Indiana-based heavy metal band Iced Earth, which he formed in 1985 under the name Purgatory.

He is also the lead singer in his political side project Sons of Liberty and, until 2021, played guitar for Demons & Wizards, his collaboration with Blind Guardian frontman Hansi Kürsch.

He pleaded guilty to crimes related to his participation in the January 6 United States Capitol attack in 2021 and was sentenced to three years probation.

[3][4] His older sister introduced Jon to bands such as Black Sabbath, Deep Purple, Alice Cooper, and Blue Öyster Cult.

[3] Schaffer went to a Lutheran school for five years, during which he developed a lot of anger and rebellion, due to the abusive nature of the pastors.

[11] The songs tell the story of a character that Jon created, called Set Abominae, who also appears on the album's front cover.

[14] The Glorious Burden was released in January 2004, after which Jon started work on two concept albums based on his Something Wicked storyline.

The first album, Framing Armageddon: Something Wicked Part 1 was released on September 11, 2007, after which, in December 2007, it was announced that Matt Barlow would be returning to Iced Earth.

In 2011, after about two years back in the band, Matt Barlow issued a statement saying that he was leaving Iced Earth in order to spend more time with his family.

From October 2011, to December 2012, Iced Earth toured in support of Dystopia, during which time they recorded the album Live in Ancient Kourion.

[19] In a video update in 2011, Schaffer and Kürsch talked about the future of Demons & Wizards and stated, that it was only a matter of their schedules lining up when they are going to start work on a third album.

Schaffer sang, played guitar and programmed the drums, but the album also featured a number of guests, including Jim Morris, Ruben Drake, Troy Seele, Howard Helm and Jeff Brandt.

[23] Once again, the album featured Schaffer singing, playing guitar and programming the drums, as well as Jim Morris and Ruben Drake.

[25] In 2012, Schaffer was featured as a guest vocalist on Anarchadia's album Let Us All Unite, performing on the track "True World Order".

[26] Schaffer has also expressed interest in doing comic book series based on the Night of the Stormrider album and the Something Wicked Saga.

[24] On January 6, 2021, Schaffer, a founding lifetime member of the far-right Oath Keepers militia,[27] was photographed among those who stormed the U.S. Capitol building.

"[34]On April 16, 2021, Schaffer agreed to plead guilty to two charges: obstructing an official proceeding of Congress and trespassing on restricted grounds of the Capitol while armed with a dangerous weapon.

He was subsequently transferred to a jail in Washington, D.C.[39] In October 2024, Schaffer was sentenced to three years of probation, 120 hours of community service and $1,200 in restitution and fines.

[45] In a 2009 interview with InfoWars founder Alex Jones discussing their mutual political views, Schaffer revealed that "My father was a John Birch guy.