The former boxing promoter Kellie Maloney has revealed that she only went public about her new life as a woman because two newspapers had threatened to expose her.

In her first television interview since announcing that she was undergoing gender reassignment, Maloney told ITV's Good Morning Britain that an unnamed newspaper had promised to expose her in February. Journalists at another newspaper doorstepped several members of her family – including her daughter – six weeks ago, she said.

Asked by the presenter Susanna Reid whether it felt good to speak publicly about her transition, Maloney said: "In a way, but it wasn't my intention. I wanted to transition very privately because of my family. They're going through a lot as well and I wanted them protected.

"Unfortunately, someone exposed me at a group I was going to. I was indoors and one day you get that dreaded knock on the door. It was a journalist – I won't say from which paper. Obviously I denied all knowledge of it and they said they were going to run the story on the Sunday so I got my lawyers involved and we had to threaten injunctions. That had been going on in February and we kept it under control."

The retired boxing promoter, who guided Lennox Lewis to world heavyweight champion, disclosed in an interview with the Sunday Mirror at the weekend that she was now living as a woman.

Maloney, 62, said she went to the Sunday Mirror with the story because she trusted it as a "friendly" newspaper that would not "ridicule" transgender people. She said she had planned to keep her private life under wraps for 18 months until she had completed her transition, allowing her family time to come to terms with any public announcement.

But, she said: "Six weeks ago another newspaper turned up at my house, and then they turned up at my daughter's house, they turned up at all members of my family's house. I spoke with my lawyer and a couple of people who have been very good to me and I said, 'Look, I'm living in a shadow. I'm living in the dark. I can't go out of my house no more. I'm terrified.'

"I started switching back to Kellie and Frank and my head was getting so confused about it.

"They said: 'We need to find a paper that would be very friendly' and I said I'd only do this as long as I've got control because previously transgender people have been ridiculed in the press and I didn't want that to happen to me and I didn't want that to happen to others."

Maloney said having her story published felt "like a complete release" and the first thing she did was to get her ears pierced because "I can do anything now". "Because they know. I'm not living two lives any more," she added.

Maloney has drawn broad support from the boxing world after she disclosed that she had privately undergone hormone therapy, hair removal electrolysis, voice coaching and specialist counselling for the past two years.

She said the negative reaction to her announcement was "like water off a duck's back", having faced criticism during her high-profile 32-year career as a boxing promoter.

Maloney said she would like to return to the sport – but only in the administrative side. "I've got all these crusades that I'd like to do, but the most important one is I'd really want to help the transgender community because they've really rallied around me."

Lewis, arguably the best known of Maloney's boxing charges, said in a statement on Sunday that he respected his former manager's new life as Kellie.

He said: "I was just as shocked as anyone at the news about my former promoter and my initial thought was that it was a wind-up.

"However, having taken some time to read Kellie's statements, I understand better what she, and others in similar situations, are going through. I think that all people should be allowed to live their lives in a way that brings them harmony and inner peace.

"I respect Kellie's decision and say that if this is what brings about true happiness in her life, than so be it."