Basking in the glow of hot temperatures and a warm feeling with his new team-mates who are about to embark on what everyone hopes will be a successful journey under serial lower-division promotion exponent Derek Adams, Kelleher is in a good place again.
It is a far cry from this time last year amid a summer of discontent at former club Macclesfield Town.
The now-defunct Cheshire outfit were in the final throes of their existence, with the Silkmen relegated to the National League after the English Football League won an appeal against a points deduction.
Worse, much worse, was to follow.
Macc were expelled from the National League last September, less than a fortnight after being wound up by the High Court, due to debts of more than £500,000.
Fortunately, Cork-born defender Kelleher had found some sanctuary at nearby Wrexham after a grim time in his career.
As Macclesfield’s captain, it had been all the more stressful, with the centre-back – one of just two players who had been under contract for the 2020-21 season – becoming a free agent following the club’s demotion from the Football League.
After a season in North Wales, the 25-year-old, who had a one-year deal at Wrexham, now finds himself back in the EFL at a club whose aspirations are all to do with promotion and not avoiding relegation – and fighting for their own survival.
Kelleher told The Yorkshire Post: “Looking at it, I have been waiting for a big move for the last two years as Covid had kind of messed that up.
“When Covid hit, it was not ideal and from May to August (2020), there were a few court cases with Macclesfield and not knowing whether they were going to be liquidated. With me being contracted there, it was a really bad situation.
“This year, I was delighted to have a full transfer window where I could speak to clubs and get offers and really go where I wanted to go and not be influenced by any club I was contracted with. It has worked out perfectly for me.
“I had a few offers in the time I was at Macclesfield and obviously, I don’t need to tell everybody, but the owner was not great.
“The club had an option on my contract and it only got extended if we stayed in the EFL and that got cancelled at about the end of August and it only left me with a week or two to get a club.
“When the club folded, it left me in a bad situation with only a few weeks left, so I had to settle for Wrexham at the time. But I am delighted to get back in the league.”
The height and physicality of Kelleher, an imposing 6ft 3in central defender, will add another welcome option in the heart of the backline for City, with the character that he showed amid fraught times in Cheshire – on and off the pitch – likely to have also marked the card of Adams.
To get out of League Two, City will need to display the right mentality allied to ability during a season when they will be the club who every rival wants to beat.
There will be pressure, but expect Kelleher – whose younger brother Caoimhín is a goalkeeper at Liverpool – to stand tall.
The pressure for him will be relative, given what he went through at Macclesfield, whose players’ wages were paid late on eight separate occasions in 2019-20.
The Professional Footballers’ Association stepped in to provide assistance to get the players through Christmas 2019, while a supporters’ trust later loaned £10,000 towards the April wage bill in 2020.
Some players chose not to train until wages were paid, while the squad boycotted a derby fixture against Crewe Alexandra around the festive season of 2019.
Strike action had previously been taken a month earlier for an FA Cup first-round tie against Kingstonian in November, 2019 when a team comprising youth team players and loanees went down to a sorry 4-0 defeat.
It was a desperate time, with the EFL acknowledging that the ‘health and well-being of players and staff had been adversely affected’ in an official statement issued by the governing body in that wretched season for Macc.
As captain, Kelleher was thrust right into the spotlight. Thankfully, he has now come out on the other side.
The Irishman, who began his career at Cork club Avondale before moving to Scottish giants Celtic, commented: “The only reason you get stronger is by going through things like that and it has made me a better person.
“I have learned so much about people and about myself and being in that situation where you are playing and not getting paid.
“I took a lot and know what it means now, really, as I have played when I have not been paid.
“I am delighted I am now at a club where it is not going to be an issue and the aspirations are there to hopefully get up to the next level.”