Richard Dysart

Richard Allen Dysart (March 30, 1929 – April 5, 2015) was an American actor. He is best known for his role as senior partner Leland McKenzie in the television series L.A. Law (1986–1994), for which he won a 1992 Primetime Emmy Award as Outstanding Supporting Actor in a Drama Series after four consecutive nominations. In film, he held supporting roles in The Hospital (1971), Being There (1979), The Thing (1982), Mask (1985), Pale Rider (1985) and Wall Street (1987). Description above from the Wikipedia article Richard Dysart, licensed under CC-BY-SA, full list of contributors on Wikipedia.
Cast

Back to the Future Part III
Barbwire Salesman

The Thing
Dr. Copper

Being There
Dr. Robert Allenby

Mask
Abe

The Day of the Locust
Claude Estee

Prophecy
Trevor Isley

The Hospital
Dr. Welbeck

Pale Rider
Coy LaHood

Warning Sign
Dr. Nielsen

The Terminal Man
Dr. John Ellis

Day One
President Harry S. Truman

Truman
Henry L. Stimson

The Hindenburg
Lehman

Bogie
Jack Warner

The Autobiography of Miss Jane Pittman
Master Bryant

Proteus: A Nineteenth Century Vision
The Ancient Mariner (voice)

An Enemy of the People
Aslaksen

It Happened One Christmas
Peter Bailey

Six Against the Rock
Warden James Johnston

The Sporting Club
Spengler

The Lost Man
Barnes

Malice in Wonderland
Louis B. Mayer

Your Alcohol I.Q.
Self

Jay Leno's Family Comedy Hour
Self

First, You Cry
Dr. Brennerman

Meteor
Secretary of Defense

People vs. Jean Harris
Judge Russell R. Leggett

Moving Target
Arthur Cambridge

The Ordeal of Dr. Mudd
Edwin Stanton

The Crazy World of Julius Vrooder
Father

Petulia
Motel Receptionist

Everything Is Terrible! The Movie
Self (archive footage)

Panther
J. Edgar Hoover

The Court-Martial of George Armstrong Custer
President Ulysses S. Grant

The Falcon and the Snowman
Dr. Lee

Riding with Death
Leonard Driscoll

Blood & Orchids
Harvey Koster

Missing Children: A Mother's Story
Hunter Burgess

L.A. Law: The Movie
Leland McKenzie

A Child Is Missing
Riley Hallihan

The Last Days of Patton
Gen. Dwight D. Eisenhower
Marilyn & Bobby: Her Final Affair
J. Edgar Hoover

Love with the Proper Stranger
Accountant (uncredited)

Mickey's 60th Birthday
Leland McKenzie

Wall Street
Cromwell

Churchill and the Generals
Gen. Dwight D. Eisenhower

Hard Rain
Henry Sears

Bitter Harvest
Dr. Morton Freeman

Shadow Game
Jerry Arnst

L.A. Law: Pilot
Leland McKenzie
Corwin
Self

Todd McFarlane's Spawn 2
Cogliostro

Spawn 3: The Ultimate Battle
Cogliostro