The former Spice Girl is now back in the UK but launched her highly successful fashion collection after relocating to Beverly Hills.
She told Allure magazine: "Living in America for six years was the happiest I think I've ever been. Yeah, it was much more accepting for a woman to have a career, as well as a man. And I loved it."
But the 39-year-old mother of four, who is about to open her first store with a shop in London, insisted: "I'm not saying I'm not happy now. I'm just as happy now!"
Beckham, formerly Posh Spice, said that she and husband David are "very equal at home," joked about having her breast implants removed and revealed that she does not shave her legs.
Gazing at an old photograph, she said of her cleavage: "I don't have them any more...I think I may have purchased them!"
Asked whether she had her implants taken out or they "just left", she told the March edition of the magazine: "Or they got removed, one or the other!...yeah".
Beckham, who revealed that she gets up at 6am to run up to four miles a day, said of finding fame with the Spice Girls: "I was never a natural. I got there in the end because I did believe that if you work hard enough, then you can achieve a lot."
She added: "I think what gave me confidence in myself was meeting the other girls. We always said we were all like rejects in our own way. We had to work hard, and they helped me accept me for who I was."
She praised her husband David as "the most wonderful man I have ever met."
"He's a fantastic father. He's incredibly talented, a wonderful husband. I supported him for many years, and he's proud of me. He supports me. We're very equal at home," she said.
Beckham told the magazine that she was bullied at school because she was "different from all the other children"
"I really wouldn't wish it on any kid, because it's horrible," she said. "I didn't go to a private school; it was a public school. It was not a very nice school."
She said that she does not shave her legs, but gets laser hair removal instead.
"(It) is amazing. You can go back for little touch-ups if you do see little hairs appearing. But I've been very lucky that I haven't had to. That was one of the best tips that (Desperate Housewives star) Eva Longoria ever gave me."
The full interview is in the March issue of Allure, on sale from next Monday.