In 2016 Wallace received an invitation as a wildcard to the 2016 Northern Ireland Open, where he lost in the first round 2–4 to Michael Georgiou. Having qualified for the 2018 World Seniors Championship, he came within one frame of winning the title, overcoming Simon Dent 3–0, Rhydian Richards 3–1 and Jonathan Bagley 3–2, but surrendered a 3–1 lead against fellow qualifier Aaron Canavan in the final to lose 3–4.