And Leinster's victory, coupled with Agen's defeat of Gloucester, has guaranteed the province's qualification for the European Cup quarter-finals.
Horgan said: "I'm delighted to get amongst the tries, it's a nice feeling being on the end of them.
"There's a lot of hard work that goes into the build-up - some of it is off the cuff stuff - but we've had that attacking philosophy for a number of years now and it's great when the moves comes off.
"We've threats all over the back line and even without a player of the calibre of Brian (O'Driscoll), who injured his calf during the week, we can still run up the tries.
"Kieran Lewis deputised for Brian well. Denis (Hickie) was involved in the build-up for a few of the tries and is playing well," added the Drogheda man.
"I thought Bernard Jackman was a stand-out man for us tonight, he puts in a lot of unseen work, and Gordon D'Arcy is in great form - he almost won our Magners League game against the Ospreys single-handedly last week."
Wind-assisted in the first half, Michael Cheika's side had nosed into a 20-5 lead by the interval with Rob Kearney and Felipe Contepomi helping themselves to tries.
Edinburgh showed promise when Hugo Southwell and Ben Cairns ended counter attach moves with a try apiece but with Chris Paterson leaving his kicking boots back home and penalty-kicking chances at a premium, Leinster's free-running style simply enveloped the Scots after the break.
Horgan and flanker Stephen Keogh added to Leinster's try-tally and Contepomi's right boot saw the Argentinian take his personal haul to 24 points.