Some actors wait tables. Some actors temp. Some actors do bar work.

Megan Riordan plays blackjack.

Sounds glamorous? She demurs.

"I'm a gambler because it's convenient. Because it funds my performing."

True, to a point. A recent trip to Atlantic City, for example, brought in $3,700 in a weekend, and funded a month of theatre workshops in New York.

But now she has reversed the relationship. Demonstrating a deft grasp of the economics of the virtuous circle, she has created a performance about her gambling.

It's called Luck, and plays at the Dublin Fringe Festival next month. A 15-minute snippet recently shown in the Project theatre revealed a spiky, high-tempo, one-woman show, part confessional monologue and part pro-gambling workshop.

The gambling she learned on her father's lap. He'd been a blackjack dealer in LA; passed over for a promotion, he quit and became a professional player. Gamekeeper turned poacher.

As a child, she had "a huge blind spot of not actually knowing what my dad did". He'd written a book, and then they built a house, so she assumed the book had paid for it. (She can't have paid much attention to the book: it was called Comp City: A Guide to Free Casino Vacations.)

Eventually, she realised what was going on in the office her father had built in the house. The full-size blackjack table and roulette wheel must have been clues. Once she was old enough, she was inducted into the team.

The team?

"There are guys who can go out on the town and have enough technique and skill to play solo. I don't."

Around the table in his office, her father taught her the ropes. She memorised the "basic strategy" charts, so she'd know how to play each hand, and learned the team signals, so she'd know what she was being told to do when they ditched basic strategy.

"Basic strategy will not win you anything over time. It keeps you breaking even. But if you can combine that with other information about cards that have come before – counting cards, and things like that – you can make it work for you."

So that's where the team comes in: working together, they can accumulate more information about cards than any one person, cutting the odds considerably. Sounds like a scam, to me.

"Scam's a very harsh word. It's not a scam. It's not illegal. It's not cheating. Everything that we do is 'advantage play'."

Still, casinos don't like "advantage play". They don't respond well to groups of people sitting around their blackjack tables, calling out cards and discussing what's likely to come up next. Which is where the wig comes in.

The wig?

"A brown wig, like Uma Thurman in Pulp Fiction."

Nice choice, but it didn't work. They were at the Mandalay Bay casino in Vegas. They came out on top and thought they'd gotten away with it, but the casino was suspicious and watched the security tapes afterwards and figured out there had been some kind of team play going on. Despite the wig, Riordan had played in her own name ("stupidly – I wanted the comp points") and she was barred. If she tries to play in the Mandalay Bay again, she's likely to be arrested, she says, for trespassing.

Gamblers disguise themselves so the casinos won't get to know them. Though women tend to be more unassuming, and can get away without wigs, the men all wear hats, to hide them from the ubiquitous cameras.

"Even when the cocktail waitress comes around, instead of tilting your head to look up at her, you stand up to talk to her, so the camera never gets a look at your face."

But disguises are also about disguising the fact there's a team at play. Riordan, who started acting at school and moved to Ireland some years ago to pursue it full-time (or as full-time as the acting profession would allow), enjoyed the theatrical side of team gambling.

"I used to really take delight in the idea of creating a character on the blackjack table. Unfortunately, nobody else seemed to take so much delight in it."

During one recent game, she played a "boneheaded" young woman, losing money. "I was totally getting into the character. And I got chastised for it later on – they were like, 'You don't need to talk so much!'"

Despite mining this material for a stage show, she is cagey about details: there are "team secrets" she can't divulge; winnings she doesn't want to specify; a team mate who has changed his name. When she refers to him by his new name, accidentally, she barks, "That's off the record." But she agrees to tell one story, as an example…

"The night my brother turned 21, at midnight, we went out on the tables. My brother, me, my dad and – I'll give you his old name – James Grosjean, who is the best gambler in the world, and a guy named Pat.

"We went out for this crazy dinner that was comped by the casino because my dad had been playing there a lot. There were lobster tails the size of footballs. After midnight, we caffeinated and then we went to the Mandalay Bay, which has a high-limit blackjack table."

Megan and her brother avoided disguises, and played together, as siblings (they look alike, so there was no point in trying to pretend otherwise). Her father was playing his favour­ite character, "the deranged Texan". He was "over first base, in a big Texan hat with big stupid glasses, doing this crazy Texan drawl which he can turn on and off".

James, who she calls "Neo", "because he's wired into the Matrix", was doing the mathematical permutations and calling the shots. "He's a genius", she says. Her father, appropriately, was the "BP", the big player: the one who bets the money and "generally draws down a lot of the heat".

The game started off slowly, with some small wins. "And then we suddenly started winning.

"My dad wanted to win $21,000 for my brother's 21st birthday. Six hours later, we walked out with it."

Riordan is writing, performing and producing her show for the Dublin Fringe, working intermittently with a director who's currently based in Edinburgh. Even still, she'll be lucky to make €21 from it. But she knows what she is: an actor who gambles, occasionally, not a gambler who acts.

"The gambling," she says, "is a nice little icing on the cake." Nice cake if you can get it.

'Luck' runs from 7-14 September,
Pantibar, Capel Street,
as part of the Dublin Fringe Festival