Harpo Marx

Arthur Adolph "Harpo" Marx (November 23, 1888 – September 28, 1964) was an American comedian and film star. He was the second oldest of the Marx Brothers. His comic style was influenced by clown and pantomime traditions. He wore a curly reddish wig, and never spoke during performances (he blew a horn or whistled to communicate). Marx frequently used props such as a walking stick with a built-in bulb horn, and he played the harp in most of his films. Description above from the Wikipedia article Harpo Marx, licensed under CC-BY-SA, full list of contributors on Wikipedia.
Cast
Got It Made
Unknown

Duck Soup
Pinky

The Movie Orgy
Self (archive footage)

The Cocoanuts
Red

At the Circus
'Punchy'

Go West
'Rusty' Panello

A Day at the Races
Stuffy

A Night in Casablanca
Rusty

The Big Store
Wacky

Love Happy
Harpo

Animal Crackers
The Professor

Monkey Business
Harpo

Horse Feathers
Pinky

The Story of Mankind
Sir Isaac Newton

A Night at the Opera
Tomasso

Room Service
Faker Englund

The Our Gang Story
Self (archive footage)

Showbiz Goes to War
(archive footage)

The Marx Brothers in a Nutshell
(archive footage)

I'll Say She Is
The Merchant of Wieners

Hollywood: The Dream Factory
Self (archive footage)

Oops, Those Hollywood Bloopers!
Self (archive footage)

Hollywood Out-takes and Rare Footage
Self (archive footage) (uncredited)

La Fiesta de Santa Barbara
Self

Going Hollywood: The '30s
(archive footage)

The House That Shadows Built
The Merchant of Wieners

Wonderland of California
Self

The Marx Brothers: Hollywood's Kings of Chaos
Self (archive footage)

Stage Door Canteen
Harpo Marx

The Unknown Marx Brothers
Self (archive footage)

Inside the Marx Brothers
Self (archive footage)

Dalí & Disney: A Date with Destino
Self (archive footage)

Too Many Kisses
The Village Peter Pan

Brother, Can You Spare a Dime?
Self (archive footage)

Hollywood: Style Center of the World
Self

The All-Star Bond Rally
Self

That's Entertainment, Part II
(archive footage)

A New Romance of Celluloid: The Miracle of Sound
Self

From the Ends of the Earth
Self

The Ten-Year Lunch
Himself (archive footage)

Humor Risk
Watson

The Big Parade of Comedy
One of The Marx Brothers (archive footage) (uncredited)

The Incredible Jewel Robbery
Nick

Hooray for Hollywood
Self (archive footage)

Snowshoes: A Comedy of People and Horses
The Jinx

Classic Comedy Teams
Self (archive footage)