Phyllis George, a vivacious Texas beauty queen who changed the face of sportscasting in the 1970s during a barrier-smashing, roller-coaster career in television, then electrified Kentucky politics as the state’s celebrity first lady, died May 14 at a hospital in Lexington, Ky. She was 70.

Her family said the cause was complications from polycythemia vera, a rare blood disorder.

As a co-host of CBS’s pregame football show “The NFL Today,” Ms. George made her name as one of the first female sportscasters and introduced a strain of personality-driven coverage that was quickly imitated around the dial.

But her national broadcast career hit a wall a decade later after a much-hyped promotion into hard news as anchor of “CBS Morning News.” She left the job in 1985 after an unhappy eight months, and returned to Kentucky to raise her two children with her then-husband, former governor John Y. Brown Jr.

“When you do something that is not right for you,” she later wrote, “you know it almost immediately.”

Ms. George burst onto the scene in September 1970, when she was crowned Miss America before a television audience of 80 million, a pageant record. At 21, she had a modern, unfussy style and preternatural ease before the cameras — swaying at the piano as she played “Raindrops Keep Fallin’ on My Head,” laughing when the crown slipped off her long brown hair.

Four years later, she was still looking for inroads into show business — auditioning for sitcoms, filming toothpaste commercials, hosting “The New Candid Camera” with Allen Funt — when her agent set up a meeting with Robert J. Wussler, the head of CBS Sports. Eager to catch ABC in the ratings, Wussler reasoned that getting women into the announcer’s booth might get more women to tune in.

After making small talk over drinks, Wussler asked Ms. George if she knew anything about sports. “Well, yeah, I’ve dated athletes,” she later recalled saying. And as a Texas native, she added, of course she loved the Dallas Cowboys. He offered her a job on the spot.

She got off to a frustrating start, later describing how in her sideline-commentary debut for the 1974 Fiesta Bowl she felt all dressed up with nothing to do. But after demanding more clarity from producers, she found her groove interviewing the top male athletes of the day, teasing personal revelations out of NBA star Elvin Hayes and tennis champ Jimmy Connors.

“A surprisingly competent broadcaster,” the Baltimore Sun declared. “Articulate and bright and clever enough to realize what she was hired for.”

Six months later, she was named co-host of “The NFL Today,” along with sports veterans Brent Musburger and Irv Cross. Their chemistry clicked, and the show was a hit.

While some critics remained focused on her dimpled good looks — dismissing her as an “airhead” or “giggly” — she continued to make headlines with her interviews. Bantering with married Cowboys quarterback Roger Staubach about his uptight “straight guy” image, she got him to blurt out that “I enjoy sex as much as Joe Namath,” his hard-partying New York Jets rival, “only I do it with one girl!” It was a quote that went the 1975 equivalent of viral.

In 1976, she became the first woman to co-host a Super Bowl broadcast. It was a milestone largely unheralded by feminists, who were uncomfortable with a woman whose springboard was a beauty pageant. Ms. George, meanwhile, made of point of declaring she herself was “not a feminist.”

Yet she was nonetheless blazing paths for other women, said Washington Post sports columnist Sally Jenkins. “I took from her that you could be a woman in a man’s business,” Jenkins said. Ms. George may have been hired in part because of her beauty, she added, but “Phyllis owned herself. She owned it. People debate what real feminism is, but for me it is what she did. Nobody used her. She used her own image.”

Ms. George also leveraged her own power in the booth. After insults from Jimmy “The Greek” Snyder, who joined “NFL Today” as an analyst, she played hardball during her contract renewal until CBS brass agreed to downgrade Snyder’s role.

Ms. George was featured on national magazine covers, and her social life — including a brief marriage to Robert Evans, the Hollywood producer behind “The Godfather” and “Chinatown” — was chronicled in gossip columns. In 1979, she married Brown, a congressman’s son who had turned Kentucky Fried Chicken into a fast-food giant. Days after their wedding, he entered the governor’s race as a Democrat.

The charismatic new couple were a sensation — “a campaign manager’s dream of media heaven,” The Washington Post observed in 1979 — constantly kissing and holding hands on the trail. “Y’all look like you’re on a damn honeymoon,” one Paducah voter groused, to which Ms. George beamed and replied, “We are.”

As first lady, Ms. George tapped her fame to raise private funds for an overdue renovation of the governor’s mansion and launched a program to sell Kentucky crafts and quilts in high-end department stores.

She also continued to work for CBS, both as a sportscaster and as host of a short-lived magazine show, “People.” And when term limits forced Brown to hit pause on politics after four years, she was ready to explore new opportunities.

In October 1984, she succeeded Diane Sawyer as an anchor of “CBS Morning News,” joining Bill Kurtis. Critics deemed her nervous and underprepared. Her gaffes were ruthlessly chronicled, and she was excoriated for a joint interview in which she suggested that a woman and the man she had falsely accused of rape find closure with an on-air hug.

Ms. George was stunned by the backlash. “I’m the least controversial person I know, to become so controversial,” she told The Post in March 1985. She was also exhausted, commuting home on weekends to Kentucky to see her two small children. In August, she asked to leave the job, according to news reports, and CBS agreed.

Phyllis Ann George was born in Denton, Tex., on June 25, 1949. Her father was an engineer, her mother a homemaker — with a small-town, family-oriented life that Ms. George was said to have craved, even as she kept reaching for bigger career opportunities.

“She was a go-getter, and she had big dreams,” said her daughter, CNN correspondent Pamela Brown. “And she left her career at the top to be a mom.”

Ms. George was studying at North Texas State University, now the University of North Texas, when she won the Miss Texas pageant on her second try.

Though she never publicly divulged her illness, her family said Saturday that she was first diagnosed with polycythemia vera in 1985, amid her career upheaval at CBS, and was warned she might have only 10 years to live. “She fought it, and fought it, and fought it,” said her son, Lincoln Brown.

After leaving CBS, Ms. George pursued smaller TV projects; launched a line of pre-marinated chicken breast entrees (“Chicken by George”) that she sold to Hormel; wrote a self-help book; created a cosmetics brand; and made her movie debut at 50 with a small role in “Meet the Parents” (2000).

Ms. George’s marriage to Brown ended in divorce. In addition to their two children, survivors include two grandchildren.

In a 2018 oral history interview, Ms. George recalled that her mother once asked her, “Why do you do all this? Where do you get your drive — all your energy?”

“I don’t think she could understand everything that I’m doing,” Ms. George said, “because that wasn’t her generation.”