THE VOICE on the telephone sounded young and excitable with a slight lilt to the familiar notes - the way you remembered "Blondie" calling "Da-a-gwood."

Penny Singleton, known to millions of moviegoers as the wide-eyed heroine of comic-strip artist Chic Young's slapstick family "The Bumsteads," has done a lot to reverse the "dumb-blond" image.

"I am," she said, "still the executive president of the American Guild of Variety Actors ever since my 'write-in' election in 1958."

"I am the only woman administrator and the only performer to hold the position."

Singleton puts in a long day starting at 6:30 a.m. and lasting sometimes until midnight. She travels constantly, sitting across bargaining tables with theater and nightclub owners to win better contracts for performers. And usually she wins.

Her latest crusade is to merge the various performers' unions in a single one. "I hold four union memberships," she noted - "AGVA, of course, as well as SAG (Screen Actors' Guild), AFTRA (American Federation of Television and Radio Artists) and Actors' Equity Association. We need a one-card union. It would help the welfare fund . . . the pension funds and it would make more room for young performers."

Born Dorothy McNulty in Philadelphia in 1912, she waited until she was 8 years old before making her debut in a vaudeville act.

She wasn't much of a singer, and she danced in her very own manner, but she had a charm that generally won any audience.

Her real stage training began in Broadway Musicals - "Good News," "Hey Nonny, Nonny," where she met such greats as Al Jolson, Jack Benny and Eddie Leonard.

Her first Hollywood role was as a "gun moll" in a William Powell film called "After the Thin Man."

In 1937 she married Dr. Lawrence Singleton. The marriage ended in divorce two years later, but she retained the name and added the "Penny."

She later married movie producer Robert Sparks, a marriage that lasted 22 years until his death.

Sparks suggested the "Blondie" series in 1939. The first one cost $95,000 to make and grossed $9 million. It was followed by 33 more until, she said, "I began to feel like Blondie."

A widow since 1963, she has two children and three granddaughters.

Her only movie role since "Blondie" was in a supporting role in Henry Fonda's "The Best Man."

In the fall of '71 she was back on Broadway, in the revival of "No, No, Nanette," and did the role again in Milwaukee later co-starring with Arthur ("Dagwood") Lake.

She speaks regretfully today of the paucity of parts for young people in the theater. "So many talented young performers, I see them everywhere I go . . . there aren't that many jobs for them."

"Show business, is a luxury business and performers are the first to feel the economic crunch," she said, and said she has no plans to retire. "There is just too much to do right now, too many people who need help."