Peter O'Malley, Stephen Dodd, Mattias Eliasson and Colm Moriarty are tied for third place at 3-under-par 69 at the Colin Montgomerie-designed Carton House Golf Club.
Dougherty, who turns 23 in five days, began his round with a pair of bogeys, but rebounded on the front nine. He birdied the sixth, then eagled the par-5 eighth to make the turn at minus-1.
The Englishman birdied the 10th, but lost that stroke with a bogey at No. 11. He closed with three birdies over his final six holes to grab his share of first.
Dougherty won earlier this year at the Caltex Masters in Singapore. Since, his best finish was a tie for sixth at the Dubai Desert Classic and he has missed three cuts in his last four starts.
'I have high expectations after winning in Singapore and I've been beating myself up badly because I've set the bar at perfection, but golf isn't like that and it's taken me a few months of miserable golf to realize that,' said Dougherty.
Eriksson started on the back nine at Carton House and had a much more up-and-down round than his fellow co-leader. He traded a birdie and a bogey over his first two holes, then recorded two birdies and an eagle the rest of his opening nine to get to 4 under.
The Swede quickly plummeted down the leaderboard thanks to three bogeys in a row from the first. Eriksson birdied the fourth, then tallied back-to-back birdies at seven and eight to join Dougherty in the lead.
'Monty didn't design this with a draw in mind so I decided to play a fade and that's what I did,' said Eriksson. 'It's a fantastic competitive golf course. Anyone who wins on this course will be very proud of himself on Sunday afternoon.'
Eriksson would be elated to hoist the trophy on Sunday for two reasons. The first is that it would be his first victory on the European Tour and the other is that the Swede missed significant time with a liver virus.
'I caught a virus in my liver in December and it completely took me out,' said Eriksson. 'I was in bed for three months, sleeping 15 hours a day. I tried to come back in Dubai, but withdrew after one day. There was no medication I could take. The body had to recover in its own time.'
Darren Clarke, Lee Westwood, David Howell, Simon Khan, Damian Mooney and Rolf Muntz are tied for seventh place at 2-under-par 70.
Montgomerie is part of a group tied for 13th place at minus-1.
Defending champion Brett Rumford overcame a triple-bogey 7 on his first hole. He tallied four birdies and two bogeys the rest of the way for a 1-over 73 and a share of 53rd place.