His works produced for the Dungeons & Dragons game include: Fiendish Codex II: Tyrants of the Nine Hells (2006, with Robin Laws), Drow of the Underdark (2007, with Ari Marmell, Anthony Pryor, and Greg A. Vaughan), Elder Evils (2007), Exemplars of Evil (2007), Tome of Magic (2006, with Matthew Sernett, Dave Noonan, and Ari Marmell), Player's Handbook II (2006).

He has also worked for Green Ronin Publishing on Warhammer Fantasy Roleplay, and made contributions to Witch Hunter: The Invisible World for Paradigm Concepts (2007).

Schwalb worked for years as a developer and staff member at Green Ronin.

[2]: 375  Schwalb designed the game A Song of Ice and Fire Roleplaying, which was previewed at Free RPG Day in 2008 and published in 2009; this was the final project by Schwalb for Green Ronin before he before he went to work for Wizards of the Coast.

Schwalb also co-wrote Divine Power, a 4th Edition D&D supplement, which made the Wall Street Journal Best-Seller list for July 2009.