McCullagh first appeared on Countdown on 2 February 2011, and beat Dave Dyer in a fairly close and high-scoring debut episode, with both players finding the nine-letter word BETTERING. McCullagh followed this up with seven more victories, including a near-perfect performance against Judy Baynes. Here, he achieved maximum points in all of the first 14 rounds, but was unlucky enough to receive a conundrum which no one in the studio was able to solve (MEGALITRE). He's also notable for having kept three of his opponents to scores under 30.
With an octochamp total of 896, McCullagh was #2 seed for the finals, second to his eventual final opponent Adam Gillard by only 7 points. He made quick work of #7 seed Andrew McNamara and #6 seed Mary Adie, with offerings including UNAWARE, INDORSED, UPSTAIR, PANTOUM, MONIKERS, NEURONE and the conundrums BEDSITTER and SINGLETON. The final proved to be closer. However, McCullagh remained on top, offering a solution to a very hard first numbers game and pulling away further with CARDIO, and despite neither player solving the conundrum, he prevailed by 113 points to 94, earning the Richard Whiteley Memorial Trophy and the title of Series 64 champion.
He returned to Countdown a year later, and with the shortened name of Ed, as one of 41 contestants taking part in the 30th Birthday Championship. He lost his only match (and with it, his unbeaten record) against the Series 66 runner-up Jonathan Rawlinson on a second conundrum, after drawing 94 – 94.
In 2012, he attended his first Countdown tournament, finishing in 2nd place at the CobliviLon tournament, losing in the final to Innis Carson. In September 2016, he secured his first tournament victory by prevailing over Dan McColm in the final of Countdown in Dublin 2016.
|#||Date||Type||Contestant 1||Score||Contestant 2||Presenters||Guest||Lex||Max|
|5196||2/02/2011||P||Dave Dyer||83 - 115||Edward McCullagh||Jeff Stelling||Rachel Riley||Gregg Wallace||Susie Dent||132|
|5197||3/02/2011||P||Edward McCullagh||97 - 28||David Clerkin||Jeff Stelling||Rachel Riley||Gregg Wallace||Susie Dent||119|
|5198||4/02/2011||P||Edward McCullagh||120 - 45||Judy Baynes||Jeff Stelling||Rachel Riley||Gregg Wallace||Susie Dent||130|
|5199||7/02/2011||P||Edward McCullagh||108 - 24||Paul Walsh||Jeff Stelling||Rachel Riley||Martin Lewis||Susie Dent||117|
|5200||8/02/2011||P||Edward McCullagh||118 - 38||Harold Sanditen||Jeff Stelling||Rachel Riley||Martin Lewis||Susie Dent||119|
|5201||9/02/2011||P||Edward McCullagh||106 - 76||Andrew Mossford||Jeff Stelling||Rachel Riley||Martin Lewis||Susie Dent||116|
|5202||10/02/2011||P||Edward McCullagh||121 - 27||Lalitha Thyagarajan||Jeff Stelling||Rachel Riley||Martin Lewis||Susie Dent||127|
|5203||11/02/2011||P||Edward McCullagh||111 - 40||Terry O'Hanlon||Jeff Stelling||Rachel Riley||Martin Lewis||Susie Dent||119|
|5273||27/05/2011||QF||Edward McCullagh||101 - 36||Andrew McNamara||Jeff Stelling||Rachel Riley||Alistair McGowan||Susie Dent||119|
|5277||2/06/2011||SF||Edward McCullagh||120 - 41||Mary Adie||Jeff Stelling||Rachel Riley||Gregg Wallace||Susie Dent||131|
|5278||3/06/2011||GF||Adam Gillard||94 - 113||Edward McCullagh||Jeff Stelling||Rachel Riley||Gregg Wallace||Susie Dent||127|
|S35||30/07/2012||S||Graeme Cole||71 - 107||Edward McCullagh||Nick Hewer||Rachel Riley||Mark Foster||Susie Dent||119|
|5623||17/01/2013||30BP||Ed McCullagh||94 - 104*||Jonathan Rawlinson||Nick Hewer||Rachel Riley||Martin Lewis||Susie Dent||117|