Written By: Ben Cosgrove

Sure, we all loved Lucy, but which one? The rubber-faced Lucy Ricardo of her classic TV sitcom, I Love Lucy? That goes without saying. But what about Lucille, the struggling but determined Hollywood starlet who spent two decades lingering in B-movie purgatory? Or the powerful Ms. Ball, the behind-the scenes TV pioneer and the medium’s first major female executive?

Truth is, Lucille Ball lived several fascinating lifetimes, many of them captured by LIFE’s photographers on her way up the showbiz ladder. She was the vice president of Desilu Productions, making her television’s first female mogul. The strain of running a business with her husband and longtime onscreen foil, Desi Arnaz, and Desi’s drinking ultimately doomed the partnership. The couple divorced in 1960, and Ball bought Arnaz out of the business in 1963. Lucy went on to star without Desi in hit sitcoms The Lucy Show (1962-68) and Here’s Lucy (1968-74). Desilu, meanwhile, remained a prolific producer of classic 1960s shows like The Untouchables, Mission: Impossible and Star Trek.

Here, LIFE.com presents photos—none of which ever ran in LIFE—of Lucille Ball, including a surprisingly sultry 1942 portrait (slide #1) by John Florea, made when Ball was known as “Queen of the B’s” for the string of sub-par films that had failed to make her a star. Years of dues-paying hard work are apparent in her eyes. And yet, there is something sweetly defiant, too, about her look: a sense that, with a little luck, her big break is just around the corner.

Man, was it ever.

Liz Ronk edited this gallery for LIFE.com. Follow her on Twitter at @LizabethRonk.

Lucille Ball, 1942. An outtake from John Florea’s 1942 photo essay on Ball, which touted her as being on the brink of fame after a decade of kicking around Hollywood. John Florea The LIFE Picture Collection/Getty Images

Lucille Ball, 1942 John Florea The LIFE Picture Collection/Getty Images

Lucille Ball in costume for the extravagant dream sequence set in 18th-century France at the center of DuBarry Was a Lady, 1943. Walter Sanders The LIFE Picture Collection/Getty Images

Lucille Ball plays upon her modeling past for Lured, a comic thriller in which she starred as a woman who agrees to pose as bait for a serial killer, 1946. Bob Landry The LIFE Picture Collection/Getty Images

Lucille Ball signs autographs for admiring seamen at one of the January 1944 galas celebrating President Franklin D. Roosevelt’s 62nd birthday. Thomas D. McAvoy The LIFE Picture Collection/Getty Images

Lucille Ball performs at one of the gala balls in Washington marking President Franklin D. Roosevelt’s birthday in January 1944. Thomas D. McAvoy The LIFE Picture Collection/Getty Images

Lucille Ball, 1944 Thomas D. McAvoy The LIFE Picture Collection/Getty Images

Lucille Ball, 1944 Thomas D. McAvoy The LIFE Picture Collection/Getty Images

Lucille Ball, 1944 Thomas D. McAvoy The LIFE Picture Collection/Getty Images

Lucille Ball, 1944 Thomas D. McAvoy The LIFE Picture Collection/Getty Images

In 1958, on the set of The Lucy-Desi Comedy Hour a collection of occasional, lavish specials that followed the adventures of the Ricardos and the Mertzes after I Love Lucy. Leonard McCombe The LIFE Picture Collection/Getty Images

The RKO studio lot was where Lucille Ball met Desi Arnaz, when they co-starred in the 1940 musical Too Many Girls. Here, in a rare color photo from his 1958 spread on the launch of Desilu Studios, LIFE’s Leonard McCombe catches the couple as they ponder their risky new venture. Leonard McCombe The LIFE Picture Collection/Getty Images

Lucille Ball is a calm eye at the center of a storm of activity at her new Desllu Studios, 1958. Leonard McCombe The LIFE Picture Collection/Getty Images

Desi Arnaz embraces Lucille Ball at the new home of their TV production empire, Desilu Studios, in 1958. Leonard McCombe The LIFE Picture Collection/Getty Images

Desi Arnaz and Lucille Ball strike familiar poses as they survey their new empire, the Desilu Studios, in 1958. Leonard McCombe The LIFE Picture Collection/Getty Images

Lucille Ball plays a matador, 1958 Leonard McCombe The LIFE Picture Collection/Getty Images