The "Keepers of the Hidden Ways" trilogy similarly placed people from the real world into a fantasy setting, making heavy use of Norse mythology.

This series, an "alternate fantasy history", takes place in a world where Mordred defeated King Arthur, establishing the Pendragon Dynasty.

Two other books in this setting, Not for Glory (1988) and Hero (1990), focus on family members of the Metzadan Mercenary Corps from the Jewish- (and others-) settled World of Metzada (Masada).

Rosenberg's novels frequently featured the theme of freedom, particularly in the Guardians of the Flame series, where the initial characters make it their life's goal to abolish slavery in their new world, and the right to keep and bear arms.

While his books of the Guardians of the Flame series have detailed descriptions of firearm technology, he began seriously dealing with self-defense issues after he thwarted a break-in into his house with a .22 LR pistol he kept in his home.

After arrival, he was told that a court order prohibited people from carrying a gun anywhere in the building, which houses family and small claims courtrooms on the third floor.

In December 2010, he was charged with possession of a dangerous weapon in a courthouse, a felony, and contempt of court, a misdemeanor, arrested, and jailed in lieu of $100,000 bond.

Rosenberg's occupations, before settling down to writing full-time, included truck driving, care work, bookkeeping, gambling, motel desk-clerking, and cooking.

In an interview following his death, his wife recalled how he came to write his most famous novel series, The Guardians of the Flame: He said, "Boy I'd really love to be in the world of my game."

Rosenberg died June 2, 2011, after a sudden respiratory depression caused a heart attack, brain damage and major organ failures.