Daniel Dafoe describes her:

She was so robust, that once, when a young Fellow would have laid with her, against her Will, she beat him so, that he lay ill of it a considerable Time.

Court records list her as a foundling who was adopted into the Clan MacThoy.  She gave her profession as a Mantua-maker.  Her skill at needlework attests to her quickness and dexterity.  It also helped in her other careers.  She was arrested on several occasions for prostitution and pick pocketing.

She frequently associated with the inhabitants near the waterfront which is most likely where she came into contact with the MacThois, a group the Ordinary described as  a "loose & disorderly people living off waste and scavenging."

She and some like minded women, the majority of them MacThoi, formed the Widows Sewing Circle, a group of women who looked out for each others interest, and serving as witness at weddings.  

Madge met several husbands at public houses near the waterfront. It was there she could find headed for sea, eager for companionship and willing to wed.  Marriage ceremonies were a simple event of leaping over a sword with her betrothed.  

If her husband failed to return from his last sea voyage, she would present her self as his widow and collect the wages due him.

On occasion, Madge didn't bother with a ceremony and claimed wages for dead seamen she never met.  During these scams, one of her sisters would vouch to the wedding.

She married Roderick Diver, a mariner serving time in Fleet prison.  When Diver wasn't at sea he worked with Madge on several different con operations.  

One involved bullying landlords out of furniture and horses.  They were just getting settled into a lucrative routine who Diver stayed out too late at a local pub.  There he was met by the press gang.  He awoke several hours later to find himself on a ship headed for the South Seas.

Madge's best cozenage was with rings.  She would dupe the unwary into buying supposed gold rings or tricking honest men into thinking a ring they had found was of great worth.  The honest man would buy out her interest in the ring.  They would then part ways, the mark with a worthless ring and Madge with the money.

Things went bad for the Widows Circle.  They had managed to bring down the wrath of the Thief- catcher, Jonathon Wild.  Madge was seized and thrown into Newgate to await her anticipated hanging.  It was at this time that Roderick Diver, long thought dead, reappeared in London Town & found her languishing in Newgate Prison.

With help from the Sewing Circle, he managed to effect Madge's escape.  They took a ship by force and a reign as sea raiders.  

See Dead-Eye Rick for the full story.

In 1720, she accepted the King's Proclamation of pardon and retired from pirating to a comfortable life in the Bahamas.