Laois, winners over defending provincial champions Dublin in the quarter-final, knew they were in a battle when Carlow grabbed the first four points of the game, with a brace from Marty Kavanagh being supplemented by white flags from Ross Smithers and midfielder Craig Wall.
Wall had a great chance of a Carlow goal in his side’s first attack when one-on-one with goalie Eoin Fleming but his kicked effort drifted wide.
Stephen Maher opened the visitors account on 10 minutes with a pointed free and by the midway stage of the half, Laois were level at 0-4 each before Carlow pulled away, with points from midfielder Adam Kenny, Marty Kavanagh and Kenny again.
With the accuracy of Stephen Maher from frees a telling aspect for Laois, they led 0-9 to 0-8 at the break.
Carlow, coached by former Waterford star Paul Flynn, continued to take the game to Laois and a Craig Wall point midway through the half edged them 0-13 to 0-12 in front. In the 49th minute Wall made a penetrating run from midfield and when the ball ran free in the Laois square, John-Michael Nolan’s goalbound shot was brilliantly blocked and cleared off the line by full back Gearóid Burke.
Laois levelled through substitute James Ryan before points from Pauric Lalor and a pointed free from Maher put them in front. But Carlow never gave up and with left corner forward Pete Shaw providing ongoing problems for the Laois defence, Marty Kavanagh pointed again for Carlow as the game entered injury time.
Despite having a chance to level it, the home side lost possession and Laois were through to a Leinster final meeting with Kilkenny.
Carlow will take a lot of positives from this game and, with a little more composure in front of goal, could have inflicted a major shock on their neighbours. They defended heroically with Conor Lawlor, David English outstanding while Craig Wall had a fine game in midfield.
Gearóid Burke, Aidan Phelan, David Freeman and Stephen Maher were best for a Laois side, whose narrow victory can be put down to greater use of possession and an edge in scoring power.
Scorers for Laois: S Maher 0-8 (0-7f), B Reddin 0-2, D Freeman, W Dunphy, P Lalor, N Foyle, J Ryan 0-1 each.
Scorers for Carlow: M Kavanagh 0-5 (0-3f), A Kenny, C Wall 0-2 each, D English (65), R Smithers, J M Nolan, D Roberts, P Shaw 0-1 each.
LAOIS: E Fleming; P Flynn, G Burke, J Finane; J Fitzpatrick, A Phelan, N Unwin; D Freeman, B Dunne; W Dunphy, P Lalor, S Maher; B Reddin, N Foyle, D King.
Subs: J Ryan for Lalor (35); Ross King for D King (43); C Dwyer for Reddin (56).
CARLOW: B Tracey; B Lambe, C Lawlor, L Kinsella; J Corcoran, D English, J Doyle; A Kenny, C Wall; R Smithers, JM Nolan, A McDonald; D Roberts, M Kavanagh, P Shaw.
Sub: J Doyle for Nolan (52).
Referee: J Keenan (Wicklow).