The 50-year-old veteran battled her way through overnight rain and morning rush hour traffic on the 26-mile course.
"I feel elated," she said, laughing, and added: "I just want to go home and take my shoes off and soak my feet!"
![[ image: width=150]](/olmedia/320000/images/_323370_zoe150.jpg)
She suffered spasms and tiredness, but reached the finishing line in The Mall at about 1600BST, 30.5 hours after setting off.
Ms Koplowitz, veteran of 12 marathons in the United States, was escorted along the route by the community safety group the Guardian Angels, and members of the 100 Yeomanry Royal Artillery Regiment.
She told the BBC she was grateful to her team and that she had a lot of physical problems being a diabetic as well as an MS sufferer.
Ms Koplowitz, from New York, competed on a pair of purple crutches and moved at about one mile an hour. She had been invited to take part by the National Multiple Sclerosis Society to launch MS Week which she described as a "privilege".
Runner's message
Ms Koplowitz said on Sunday night: "The marathon is really only a metaphor for life.
![[ image: width=150]](/olmedia/320000/images/_323311_zoe_quote_150.gif)
"I am sending a message to everyone that you don't need to win the race to be a winner in life.
"Everybody faces marathons each day whether it be looking after kids, parents or at work - it is about finishing what you have started."
More than 30,000 runners completed the race, including Barbara Cole, 43, and Mick Gambril, 46 who were wed en route.
The couple were married by a registrar at a Jacobean mansion at Greenwich, before running the remaining 24 miles.
Charity haul
The race was won by the Moroccan Abdelkader El Mouaziz in two hours, seven minutes and 56 seconds.
The women's race was won by Kenya's Joyce Chepchumba, whose time of two hours, 23 minutes and 21 seconds was a new course and world record.
But the day was about the huge number of amateurs and fun-runners, many of them raising money for good causes, including the Kosovar refugees.
The race is expected to raise more than £16m for charity.
African success in London Marathon
(18 Apr 99 | Sport)
Runners step up for big day
(18 Apr 99 | UK)
How to survive a marathon
(16 Apr 99 | Medical notes)
The London Marathon
(14 Apr 99 | Sport)
The London Marathon
National Multiple Sclerosis Society
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