2015 •
World Memory Championships (16-18 Dec., Chengdu, China): 1st place overall. Mullen became the tenth individual, and the first American, to win the world championship since its inception in 1991. He also received the title of international
grandmaster of memory, the highest title bestowed by the World Memory Sports Council, at this event. Mullen became the ninth individual to win the American national championship since its inception in 1998. •
US Open (2–3 July, Los Angeles, California): 1st place overall. With 8,794 total points, Mullen achieved the then-highest total score in memory sports history (taking into account adjustments in scoring standards), giving him the world No. 1 ranking. •
European Open (3-4 Dec., London, UK): 1st place overall. With 9,143 total points, Mullen broke his earlier mark for the then-highest total score.
2017 •
World Memory Championships (IAM) (1-3 Dec., Jakarta, Indonesia): 1st place overall. Most world records broken at the event, 4. With 9,061 total points (adjusted), Mullen broke his earlier record for the then-highest total score.
2021 •
Pan American Open (Memory League) (15-16 May): 1st place overall. Mullen competed alongside 15 other online qualifiers using the Memory League format, which consists of digital, head-to-head matches composed of shorter disciplines. In the final, Mullen defeated Ryo Kobayashi of Japan.
2022 •
Memory League World Championship (16-31 Jan.): 1st place overall. Mullen competed alongside 15 other online qualifiers in the fourth rendition of the Memory League World Championship, first held in 2014 under the name Extreme Memory Tournament. In the final, Mullen defeated 2019 IAM World Memory Champion
Andrea Muzii of Italy.
2023 •
Memory League World Championship (8-29 Jan.): 1st place overall. Mullen again defeated
Andrea Muzii in the final. ==Records==