Gray and fellow Dunedin triathlete Steve Prescott are among early favourites to win a medal at the ITU world championships on Australia's Gold Coast.
The 46-year-old Gray will be contesting the 45-49 age group and Prescott the men's 55-59.
Both won their respective age groups at the national championships in Wellington in March to gain automatic qualification to the world championships.
For Gray, a property manager with the University of Otago, it will be his first time in world competition after 25 years of contesting top multisport and endurance events.
He survived a tough introduction to triathlon in 1984, at a time when the sport was still trying to gain credibility in an environment dominated by swimming, cycling and running.
He was studying at Canterbury and Lincoln universities at a time when world champion Erin Baker and national champion John Hellemans were influencing athletes in Christchurch.
"They really drove the growth of the sport," Gray said.
"Back then you'd race these guys and be inspired.
"It's unfortunate that it's something you don't get a lot of these days."
Gray moved to Dunedin for work in 1987, and his interest in the sport took off when he began flatting with Mark Elliott.
He remembers a field of 300 fronting up for the Otago triathlon championships in the early 1990s.
Danyon Loader was swimming for one of the top teams, and internationals John Knight and Brendon Downey battled it out for individual honours.
Gray said Elliott and people such as multisport scientist Jim Cotter and local identity Ray Hope had boosted his interest in triathlon.
He recalls Elliott's training regime.
"They were long hard sessions.
"We'd be out for hours at a time and I'd come back shattered.
"At times Mark would train so hard, I'd be totally destroyed.
"It's no coincidence that New Zealand has had such success in triathlon and now cycling since Mark's taken over the reins of high performance.
"He's just so motivated, organised and focused."
Elliott and Gray have remained good friends.
Last Christmas, the pair caught up while on holiday at Hawea and hatched a plan after Gray said he was thinking about trying out for the world championships.
"Mark suggested some sessions similar to those of Bevan Docherty.
"But of course with work and family commitments, I don't have the time.
"Besides, it would probably kill me."
Gray returned from holiday motivated to do well at the national championships in Wellington in March, and went on to win the 45-49 age group and qualify for the world championships.
Success runs in the Gray family.
Gray's wife, Anne (nee Condie), is a former national swimming champion.
Their children are excelling in various sports.
Mary (14) has had top results in running, rowing and mountain biking, as well as featuring in canoe polo, water polo and football.
Michael (12) is an Otago age-group swimming and water polo representative, while George (10) is keen on all sports but has a passion for football.
Other triathletes selected from Otago for world age-group competition are Karen Blackwood, Marion Maxwell, Andrea Alvines, Tamsyn Hayes, Katie Menzies, Rebecca Grant, Johanna Jackson, Tessa Malloy, Emma Rathbone, Emelia Kinnard, Steve Prescott, Nick Taylor, Lindsay Dey, Stephen Colpitts and Mark Howard.
Triathletes from Otago contesting elite titles are Nicky Samuels and Tony Dodds.
Sarah Bryant is another but is now based out of Palmerston North and will be racing for age-group honours.
Murray Gray : Triathlete
Age: 46
Occupation: Property manager.
Family: Wife Anne, children Mary (14), Michael (12), George (10).
Achievements: National age group champion 2009, City of Christchurch challenge champion 2004, second veteran Gold Rush 2004, third overall Otago Rail Trail 2008, Otago multisport championships open title 2002, won veteran section Otago duathlon championships 2004, fourth veteran Coast to Coast one-day section 2003.
