Rowan's first tournament was COLIN X in 2014, pitted against Jeff Clayton, Rob Foster, Michelle Nevitt, Mike Brown, Andy Platt and Thomas Carey. He finished 20th out of 48, on 3/6 wins and 355 points. This was followed up later in the year by 7th/40 in CoStAl.
On 5 October 2020, Rowan set the highest ever score in a standard human v human game of Countdown on Apterous, by virtue of the highest ever scoreline of 176 – 166 against Hazel Drury.  A week later, on 12 October, he recorded the first maximum-scoring game on Paul Anderson's Countdown-based YouTube show ZoomDown; in the penultimate round, Rowan made a spectacular solve in a 6-small numbers pick, featuring two 10s, in which he produced a four-digit number before cancelling down to reach the target.
|#||Date||Type||Contestant 1||Score||Contestant 2||Guest||Lex||Max|
|6224||8/10/2015||P||John Hardie||104 – 97||James Rowan||Charlie Stayt||Susie Dent||145|