Dressed in a cream coat with fur trim, a vintage orange hat and an orange leather belt, she beat around 100 women to the title of Most Stylish Lady.
Understated elegance was the order of the day as glamorous women donned fur coats and classic hats to cover up on the rain and windswept race course.
Many women went for neutral colours, teamed with brightly coloured accessories and head pieces.
Former Dragons' Den investor and Newstalk presenter Norah Casey had recovered from her Christmas cold in time to help judge the competition.
"I come here every year and we are having a great day -- the style is just incredible," said Norah, who also co-presents Friday's edition of RTE magazine show Today.
"We were looking for someone with classic tailoring and someone who was appropriately dressed for post-Christmas at Leopardstown.
"We just thought she stood out from everyone else," Norah said of Geraldine.
Geraldine said she was shocked at being named most stylish woman as dressing up is not something that she gets to do often.
"I wasn't expecting it at all," Geraldine, who lives in Kinsale, told the Herald.
"I have four kids and we were very busy at Christmas so the outfit was put together with what was in the wardrobe."
Despite the wet and windy conditions, a strong crowd of 16,409 turned out for the third day of the Leopardstown Christmas festival -- up 1,200 on last year's attendance.
A host of well-known names were among the eager race goers, including Ryanair boss Michael O'Leary (inset).