Adler was born in Paterson, New Jersey on October 2, 1956. In the mid 1960s, his family moved to Nanuet, Rockland County, New York and later to Massachusetts. Charlie was given the nickname “Beanie” due to always wearing a Beanie cap. His sister Cheryl Adler is a psychotherapist who wrote the book Sober University. Growing up, Adler was a “TV junkie”, a fan of The Three Stooges, Rocky and Bullwinkle, and Irene Ryan's Granny Moses from The Beverly Hillbillies.
Adler's first professional acting job was in a commercial in 1971. Afterwards, he took a break from acting. During this time, Adler worked a variety of jobs, including waiter, janitor, paper delivery man, floor stripper, house painter, remedial reading teacher, and caretaker for an Episcopal church.
In 1984 and 1985, he starred as Arnold Beckoff in Torch Song Trilogy, for which he was nominated for the 1985 Helen Hayes Best Actor Award, in New York before moving to California in 1986.
Adler's first animation role was recorded in New York, voicing Spike in Rescue at Midnight Castle.
In 1985, after convincing the head of the Abrams, Rubiloff, and Lawrence agency to allow him to audition for their voice over department, Adler went to a private audition for Ginny McSwain and Arlene Thornton. An agent had praised him in front of them as the “next Frank Welker”. McSwain recalls that “he blew their minds” but Adler claims that initially they had no interest in him. Having no demo, they arranged for him to record an audition. Adler improvised characters on the spot during the tape, which impressed both McSwain and Thornton, however left him so embarrassed with his behavior that he performed with his back to them and his face hidden with a hat and sunglasses.
His voice acting career took off. Adler landed the roles of Nat Smurfling in the fourth season of The Smurfs, Rowdy Roddy Pipper in Hulk Hogan's Rock 'n' Wrestling, Silverbolt in The Transformers, and Eric Raymond in Jem.
After portraying Ralph / Rita in The Redd Foxx Show, he was completely dissatisfied with working on a TV series. In an interview for The Magic Behind the Voices, Adler commented on the experience: “you spend your whole life going, 'God, I just want to be in a TV show and have a parking space.' Then I got it and it was just so not what I wanted to do.” That is when animation “grabbed him”.
He became active chiefly in animation, his roles include reprising as Spike in My Little Pony, Low-Light in G.I. Joe, Mr. O'Greasy in A Pup Named Scooby-Doo, Deputy Fuzz and Tex Hex in Bravestarr, Cavey, Jr. in The Flintstone Kids, Pinky Dalton in The Good, the Bad, and Huckleberry Hound, Quark and Zappy in Rockin' with Judy Jetson, the Hamburglar in a few McDonald's commercials, Mad Dog, Hacksaw, and Howard Huge in TaleSpin, Dripple in Tom and Jerry Kids, and the bear from darkest Peru in Hanna-Barbera's version of Paddington Bear.
In 1990, Adler lent his voice to Buster Bunny on Tiny Toon Adventures. The show's producer Tom Ruegger recalled that he and voice director Andrea Romano insisted Steven Spielberg cast Adler, due to his bringing “a great deal of energy” to Buster. During season 3 of the show in 1992, Adler abruptly walked off from the show after a dispute with the producers. While voice actors with smaller roles in the show were given starring roles in Tiny Toons' successor Animaniacs, Adler had become upset when he had not been given a role in that show. John Kassir replaced Adler as the voice of Buster by the end of season 3.
In 1993, Adler went on to portray Chance “T-Bone” Furlong in Swat Kats: The Radical Squadron, Bill in The Terrible Thunderlizards, Ickis in Aaahh!!! Real Monsters, Ed Bighead, Bev Bighead, and other characters in Rocko's Modern Life, Stalker Slaughter in Captain Planet and the Planeteers, and Screwball Squirrel and reprising his role of Dripple in Droopy, Master Detective.
In 1995, he voiced several characters on multiple What a Cartoon! episodes, such as Gramps, Awfully Lucky, Yoink! of the Yukon, and No Smoking. In the latter, he played Cow, Chicken and The Red Guy. No Smoking was a pilot created by David Feiss, which was greenlit to be a series in 1997 with Adler on board to reprise his characters, which now included a new character, I.R. Baboon, for a new segment within the show. The hit program Cow and Chicken ran from 1997-1999, receiving multiple awards and nominations, including an Annie Award for Outstanding Individual Achievement for Voice Acting in an Animated Television Production for Adler as Cow.
His voice directing career began in the late 1990s with Rugrats and continued with other Klasky Csupo franchises. Adler has since directed The Wild Thornberrys, All Grown Up, The Marvelous Misadventures of Flapjack, The Replacements and many more.
Adler also voiced Dr. Peacock in the Froot Loops commercials, Patrick Winks and Mr. Hornsby on Jakers! The Adventures of Piggley Winks, and SAVO on Danger Rangers and Mr. Whiskers in Brandy & Mr. Whiskers
In 2002, Adler, with help from David Feiss and Michael Ryan, directed his own short movie No Prom for Cindy, a teen dramedy about a high school girl (played by Adler himself) who fears she may be a lesbian after kissing her best female friend and refusing to make out with a boy who asked her to the prom.
In 2007, Adler voiced in Michael Bay's live-action Transformers film series, providing the voice of Starscream after having voiced the characters of Silverbolt and Triggerhappy in The Transformers. Just as Chris Latta voiced both Starscream and Cobra Commander in the Sunbow cartoons, Adler voiced Cobra Commander in G.I. Joe: Resolute and G.I. Joe: Renegades.