The designer won the Fashion Force award at the 25th Annual Glamour Women of the Year Awards in New York.
Referencing her habit of keeping a straight face for photographs, the former Spice Girl tweeted a picture of herself on stage with a beaming smile alongside the caption: “Yes she smiled! I’m happy.”
In a tribute by friend and former Desperate Housewives star Eva Longoria, Beckham was described as a Woman of the Year because she is bold, loyal and funny.
“She’s bold enough to curate a style all her own. She’s a loyal, giving friend, and funny, funny, funny!” Longoria is quoted as saying on the Glamour website.
Other winners at the ceremony at Carnegie Hall in Manhattan included transgender reality star Caitlyn Jenner, formerly the US Olympic athlete Bruce Jenner, and actress Reese Witherspoon.
Jenner, who was named Woman of the Year, told the crowd at Carnegie Hall that the six months since she came out as a woman have been “the most eye-opening experience of my life”.
She said that before she transitioned to a woman, she stayed at home most of the time, feeling alone.
“Now I actually like going out, and I like being myself,” she said.
“I’m very happy to be living on the other side.”
She described going through “many, many years of isolation” before coming out.
“And I came to the conclusion that, you know what? Maybe this is why God put me on this earth, to tell my story ... and maybe make a difference in the world,” said Jenner.
“What a great opportunity in life to have.”
Reese Witherspoon gave the final speech of the night, speaking passionately about female ambition.
“I believe ambition is not a dirty word,” she said.
The Oscar winner co-founded a production company, Pacific Standard, which aims to make films featuring strong female lead roles, “not the wife or the girlfriend, but the lead,” said Witherspoon, as a way to fight the gender pay gap in Hollywood.