A native of Hampton, Virginia, Wallace attended the University of Texas at Austin alongside Robert Rodriguez. There he received a Bachelor of Science in Communications and Screenwriting. Afterwards, he headed for Los Angeles, where he worked briefly for Roger Corman. Later, he became an executive story editor and writer for the Syfy series Eureka. Wallace's first assignment for DC Comics was writing a short story staring Vixen for the DC Universe Halloween Special. He then wrote Final Crisis Aftermath: Ink and Titans #24—38. He was the writer of Mr. Terrific but the series was cancelled after eight issues.