Once the site of a famous monastic school that was the alma mater of St Columbanus, it was used after the First World War to re-house injured soldiers returning home from the trenches.
Joe discovers the difficulties experienced by the twelve soldiers who lived here as a bridge to the mainland was only built in the 1950s making access to and from the island extremely challenging.
And he hears how only one of the soldiers endured the island's demanding conditions, farming on Cleenish until he died at the age of 101.
However, the former soldier did retain an extraordinary friendship with two of the other inhabitants of the island whose grandchildren are visiting their former home on Cleenish for the first time and Joe shows the veteran's relatives round the small island while they discuss their grandfathers' friendship.
The presenter also learns about another population introduced to Cleenish at the end of the nineteenth century by the landlord, Captain Collum who brought European brown hares to the area for the first time.
Joe discovers why the hares initially became residents of Cleenish and how the disappearance of the breed is good news for the native Irish hare.
This series will see Joe discover a whole range of new fascinating stories, remarkable people and stunning vistas across the country, many of them from places that he had never set foot in before.
Viewers can join in the conversation by tweeting along with @utv during the show using the hashtag #LesserSpotted.
Lesser Spotted Ulster returns to UTV on Friday 18 July at 8pm.