But she was then adopted by another family member who then went on to rename her - and it was only when she was eight-years-old that she was told the truth about how she came into the world.
Two decades later, wanting to meet up with the man who found her, she made a newspaper appeal and Campbell saw the story and came forward - and they have now met again in Central London.
Sheikh said: "I am so overwhelmed, this is unbelievable. I've been waiting 15 years to meet him and he's finally here. He was the second person to hold me after my mother, it's incredible."
Campbell was shown Sheikh's newspaper appeal earlier in the week for the man who had saved her by a work colleague at delivery firm DPD, who immediately recognised him as the man who had performed the good deed 20 years earlier.
He had kept photos and clippings about Sheikh from the time he found her, hoping he would one day see her again.
He said: "This is a beautiful, beautiful day. I am so glad she has got in touch after all this time, I have never forgotten her. I can't believe she found me."
Campbell had gone to the phone box, near where he lived, to call his parents in Guyana in the middle of the night, because they had a five-hour time difference.
He initially thought the baby girl was discarded chip wrapper - not realising the new life swaddled inside them.
He said: "As I was walking towards the phone box, I could see what looked like chip wrappers on the floor - it annoyed me that people couldn't pick up their mess.
"But just before I got to the door, I realised there was a tiny life form wrapped inside. She was an innocent, sweet little thing, just laying there gargling. As far as I can see, I did what anyone else would have done."
Campbell tried to stay in touch with Sheikh, who received the first name of Kiran from her adoptive parents, by taking cards, money and gifts to social services.
He even asked if he could adopt the baby, but was told he could not because he was not married at the time.
Campbell continued trying to make contact for seven years, until social workers told him to stop - but Sheikh said she never received his gifts, and was given no information about him.
She added: "I don't know why they didn't tell me about him. All I received were photocopies of the outsides of the cards he sent, not even what he'd written inside.
"I cannot believe they didn't put anything on my file about him. They really could have done something - people don't do what he did, not like that."
Speaking on ITV's Good Morning Britain today, Campbell said: "My work colleague ... came in yesterday morning and threw the paper at my desk and he said 'Joe, this is you'."
Talking about their reunion, which has made front-page headlines in Britain, Campbell added: "Well it was emotional, it was happy - Okay, I shed a few tears back whilst waiting, I did my best not to cry yesterday because big boys don't cry.
"But it's one of the happiest days of my life because I never stopped looking for her - I was always hopeful that someday, somehow I'll find her before I finally part this world.
"She is my family - I told her, I said you've got siblings, Okay we're not blood related, but we are."
And Sheikh said: "It was just overwhelming - I'd wanted since I was eight years old, that's a long time to turn 22, I'm still overwhelmed now. I think it's going to take a few days to sink in.
"I didn't think it would happen that quickly. His children were speaking to me yesterday. I'm not angry, I forgive her (my mother), she wrote me a letter saying sorry, I forgive her.
"I would love to just meet her and forgive her completely. I hope she doesn't feel bad or anything - I would never want her to feel that way."
As she grew up Sheikh had suspicions she was adopted because her parents were much older than her friend's parents and had different skin colour to her.
When she was 18, she received her files from social services, but there was little more information about the Good Samaritan who saved her, prompting the search that led to her newspaper appeal earlier this week.
But she has never met her real mother, who had abandoned her as a baby because the father was violent and she already had six children.
The police made a huge appeal for the parents to come forwards at the time, but were unsuccessful - until Sheikh's mother gave birth to her eighth child two years later.
She then admitted leaving the baby, but was not prosecuted and later disappeared.
Sheikh received a letter from her mother apologising for her actions when she was aged three, but that was the last contact she had.
She has since been in touch with her other siblings but only maintained contact with one called Zoe, who was also put up for adoption and now lives in Florida.
Her father is in prison in Canada for attempted murder after he stabbed another ex-girlfriend 30 times.
Another big shock came when the two realised Sheikh had grown up just streets away from where Campbell had lived until 1997 in Forest Gate - with the two having probably crossed paths for years.
Campbell, who now lives in Bell Green, South London, did not know his own biological mother, who died when he was three, and believes this may have influenced his kindness.
He said: "I wanted her to have parents. My stepmother looked after me as if I was her own, and I wanted Kiran to have that too."
