Born and raised in London, Anrold played football and ran the 100 metres, before being awarded a rugby scholarship to attend Cranleigh in Surrey where director of rugby Andy Houston became a mentor.
Harlequins were keen to bring him into their academy, but as a scrumhalf. Having played for the Ireland Under-18s and under-20s, he opted for Ulster in 2015.
He made his Guinness PRO12 debut as an 18-year-old against Newport Gwent Dragons at Rodney Parade in March 2015 and completed the season as Ulster Rugby's Academy Player of the Year.
In February 2016, Arnold made the move to Munster from Ulster where he made 14 senior appearances including his Champions Cup debut, starting on the wing against Oyonnax in Charles Mathon in January.
The former Exiles representative joined Munster on a two-year deal at the beginning of the 2016/17 season. Sustained a knee injury during the pre-season training and is ruled out for the opening period of the 2016-17 season.
Arnold made his senior debut v Benetton Treviso, November 2016, Thomand Park. The promising centre has played once for Munster as he enters the 2017-18 campaign.
In 2018 Arnold signed an extension that will see him remain at the club until 2020.
Ahead of the 2018/19 season, Arnold has played 19 times for Munster scoring 25 points and has featured 5 times in the Champions Cup.
In October, he was called into the Ireland squad ahead of the November Tests.
JW October 18
|2016 - present|
|2015 - 2016|
|2015 - 2016|
|2018 - 2019|