Betty White, the trailblazing television star whose more than eight-decade career saw her go from unforgettable roles on “The Golden Girls” and “The Mary Tyler Moore Show” to becoming a cultural icon in her 80s and 90s, died Friday, TMZ reported. She was 99.

The eight-time Emmy winner held the record for the longest TV career of any entertainer — making her debut in 1939 when the medium was just an experiment and going on to appear as an actress, host and in-demand guest well into her 90s.

But she’ll be best remembered for her scene-stealing roles in two pioneering sitcoms — as the promiscuous cooking show host Sue Ann Nivens on the “The Mary Tyler Moore Show” in the 1970s and sweet-natured simpleton Rose Nylund on “The Golden Girls” in the 80s.

“If an actor can get one great character in their career that’s something,” Syracuse University TV professor Robert Thompson told The Post.

“Those two shows are her great legacy 
 because people will continue to watch that stuff. They’ve really got classic status.”

White was born in the Chicago suburb of Oak Park on Jan. 17, 1922, the only child of parents Tess, a homemaker, and Horace White, an electrical engineer.

The family moved to California a few years later — eventually winding up in Los Angeles, where the future star grew up in the shadow of Hollywood.

She was bitten by the showbiz bug when she wrote herself into the lead role of a school play. She then scored her first TV gig just a month after graduating from Beverly Hills High School in 1939 — singing “The Merry Widow” on an experimental local channel.

The appearance, at age 17, came months before the medium was introduced to the masses at the New York World’s Fair.

“Betty White’s career in television goes back, for all intents and purposes, before television,” said Thompson. “Nobody had a TV in 1939.”

She took a break from the small screen during World War II,  working in the American Women’s Voluntary Services and briefly marrying a fighter pilot named Dick Barker, but returned in the late 1940s with small parts on a local station.

By then, just under a thousand people in Los Angeles had a TV, White said in her 1995 memoir.

White’s first big role was as a co-host on the daytime talk-show “Hollywood on Television” — filling five and a half hours of air time, six days a week with freewheeling banter, celebrity interviews, skits and live commercials

The show was a hit.

“It was us or the test pattern,” White once quipped — but she said her second husband, Hollywood agent Lane Allen, couldn’t handle being married to a busy career woman and the union fell apart after two years.

In 1952, White co-created and starred in a Saturday-night sitcom called “Life with Elizabeth” — becoming one of TV’s rare female producers and earning her first Emmy nomination.

She continued her pioneering role both in front and behind the camera with the short-lived NBC talk show “The Betty White Show” in 1954.

Some stations in the South threatened to pull the show off the air over the inclusion of African-American tap dancer Arthur Duncan in the cast, but White famously told them to “live with it.”

“She was probably one of the nicest, grandest, greatest people I’ve had the chance to meet in my life,” said Duncan in 2018. “Whenever she walked into a room, it lit up.”

During the 1960s, White became a regular guest on TV game shows — where she met her third and final husband, “Password” host Allen Ludden, who she stayed with until he died in 1981.

In 1973, the already popular “The Mary Tyler Moore Show” was looking to cast the character of Sue Ann Nivens, described in the script as an “an icky-sweet Betty White type” — and ended up hiring the real thing.

Nivens — a cooking show hostess at Mary Richards’ fictional TV station — was “cloyingly sweet on the surface and something of a dragon underneath, with a tinge of nymphomania,” White wrote in her 1995 memoir. “I was born for the role!”

For the 1970s, a character like that was “a big deal,” Thompson said.

“Sue Ann Nivens was a woman who enjoys sex and does things that allow her to satisfy that enjoyment. Betty White as Sue Ann Nivens was doing in the 1970s what ‘Sex and the City’ wouldn’t get around to the late 1990s,” he said.

The job netted White her first — and second — prime-time Emmy awards.

She followed the statue up with a third when she was cast on NBC’s “The Golden Girls” in 1985.

Initially, 63-year-old White was expecting to play the man-hungry Blanche Devereaux, but the pilot director felt it was too similar to her character on the “Mary Tyler Moore Show,” so instead she was gifted with the loveably dim-witted Rose Nylund.

It was an inspired decision, according to Thompson.

“The way she could deliver that sort of naive ‘I don’t know what you’re talking about’ look whenever someone started talking about sex — but same time, we know she’s a widow,” he said.

“It was so much fun knowing who Betty White really is uttering those words.”

The sitcom about four older ladies was an unlikely worldwide hit, running for seven seasons followed by the spin-off “The Golden Palace.”

Several more short-lived sitcoms followed in the late 1990s, but as White travelled through her 70s and 80s, she carved out a prolific career guest starring on everything from “Noddy” to “30 Rock” — and even had a short stint on “The Bold and the Beautiful.”

But she also cultivated the greatest role of her twilight years: Betty White.

Appearing as a larger-than-life version of herself cracking bawdy jokes that younger guests could never get away with, White again became a sought-after personality on talk and game shows.

“Betty White for the past 30 years turned herself into a piece of performance art,” said Thompson.

“If Betty White was scheduled you knew you were in for some fun. The older she got, the more television tolerated more candid discussion, she really became known [for] you never know what’s going to come out of her mouth.”

The pinnacle of this period came in 2010, when White’s fans began a Facebook campaign called “Betty White to Host SNL (Please).” With almost half-a-million people signing on, she became the oldest person to ever host the show at 88 and won her seventh Emmy for the performance.

She followed that up with six seasons on TV Land sitcom “Hot in Cleveland,” and hardly slowed down as she hit her 90s — hosting prank show “Betty White’s Off Their Rockers” and “Betty White’s Smartest Animals in America,” where she was able to tap into her lifelong love of animals.

“I’m just grateful to be working and that starts at the beginning,” White told The Post in 2018 at age 96.

“When you start out you’re so grateful to have a job 
 and you carry that feeling through your whole career. At least I have.”