2013 was the breakthrough year at Turf Moor for the highly rated defender, who joined the Clarets from League of Ireland side Cork City during the 2010 January transfer window.
The tall centre-back cost Burnley a six-figure fee as they beat off stiff competition for the capture of the Republic of Ireland under-21 international.
Long signed a three-and-a-half year deal at Turf Moor and, after finally breaking through into the first team in the 2012/13 season, agreed a new two-year extension in February 2012, taking him to the summer of 2015.
His burgeoning talent was then rewarded further when, shortly after making his Premier League debut at Newcastle in January 2015 - and suffering a cruciate knee injury that ruled him out for the remainder of the campaign - he signed a further two-year deal carrying through to summer 2017.
That was extended by a further year in October 2016, keeping the Irishman contracted to the Clarets until the summer of 2018.
Long spent his first few months at Burnley as a regular in the reserves before joining local neighbours Accrington Stanley on loan in 2010/11 and returning to the Crown Ground for a second succesful spell the following season.
He scored his first League goal in English football in Stanley colours at Plymouth Argyle in October 2011 and then, after John Coleman took over as Rochdale manager, followed him into League One with a loan move to Spotland in January, 2012.
After playing 16 times for Dale, Long was called up by the Republic of Ireland under-21s for the first time for a European Championship qualifier in June, 2012.
Long started the 2012/13 on loan at Portsmouth but following his return to Turf Moor became a regular member of the first-team squad and made his full debut against Watford in December, 2012.
The defender suffered a cruciate knee injury on his Premier League debut in January 2015, forcing Long out of action for nine months.
On his return, Long joined League One side Barnsley in November 2015 on a one-month loan, followed by a loan move to MK Dons in March 2017.