In February 2015 at the German Darts Championship, Murnan beat Michael Barnard 6–5, Ian White 6–4 (averaged 99.72) and Brendan Dolan 6–4 to play in his first PDC quarter-final. He fell 4–0 down to world number one Michael van Gerwen, before closing to 4–3 with a 12 dart leg, but went on to lose 6–4.[7]
Murnan's title saw him finish the third highest of the non-qualified players on the Pro Tour Order of Merit for the 2016 World Championship.[11] He played 2012 runner-up Andy Hamilton in the first round and, having trailed 2–1 in sets (missing five darts to lead 2–1 himself) and 2–0 down in legs, Murnan managed to pull off a comeback victory to set up a second round match with Alan Norris, which he lost 4–1.[12][13] He was knocked out in the fourth round of the UK Open 9–8 by Jelle Klaasen.[14] Murnan's first quarter-final of 2016 was at the 11th Players Championship event and he was edged out 6–5 by Joe Cullen.[15] He qualified for the World Series of Darts Finals and again lost 6–5 to Cullen.[16] He was also knocked out in the first round of the Players Championship Finals 6–0 by Jermaine Wattimena.[17]
Murnan lost his PDC Tour Card at the end of 2018 despite managing to qualify for the Grand Slam of Darts for the second consecutive year. However, he won it straight back at UK Q-School in January 2019 via the Order of Merit, sealing at least another two years on the ProTour.
Murnan again immediately obtained his Tour card back in UK Q-School 2021. During the season he qualified for 2021 European Championship, making his debut at this major event. In the First round he los 4-6 with Adam Gawlas. At the end of the year, Murnan qualified for 2022 PDC World Darts Championship, returning to this venue for the first time from 2017. He won his First round match against Paul Lim 3-2, but lost in the Second round 2-3 with Nathan Aspinall.[20]
Despite appearing only at 2022 UK Open, where he lost in the Second round, Murnan was able to hold his Tour card after finishing the season in top 64 at 63rd place, without qualifying for the World Championship.
In 2023 he played only at 2023 UK Open, losing in the Third round against Adrian Lewis 0-6. Throughout the year Murnan qualified for only one European Tour event and ended up outside of top 64 at the end of the year 2023, therefore he lost his Tour card.
Having succeeded four times previously, Joe Murnan failed to get through Q School 2024 and missed out on a card for only the second season in 13 years.[21]