McConaughey worked with the actor, who died on Thursday following complications from Lou Gehrig's disease, on the 2012 coming-of-age drama "Mud."
"Look, I'm not going to trivialize that situation, I just heard about it for the first time," the actor said. "But I always told [director] Jeff Nichols this, look in 'Mud,' the whole trailer for 'Mud' could be Sam Shepard sitting in that green chair telling the boy about who Mud is. It would be about a two-and-a-half minute trailer, but it would have been really badass."
See how more stars reacted to Sam Shepard's death:
Stars react to Sam Shepard's death
Stars react to Sam Shepard's death
Jeanne Moreau, Sam Shepard thank you for enlighten us at 24 frames per second. RIP https://t.co/fPi6HTLnzp
A great man of the theater has passed. Thank you, Sam Shepard. RIP.
Oh MAN. #RIPSamShepard https://t.co/5RMcUMI4az
Sam Shepard is one of the greats. These eyes saw so much, and he wrote of what he saw with fearless, timeless hone… https://t.co/QmqU5HkugG
Sam Shepard was a towering figure in American theater and film. He indeed had "the right stuff." His voice will tru… https://t.co/g2iEJw7P2m
Everyone who ever met him or worked with him even for a minute is going to share their Sam Shepard story and it's going to be fantastic.
Damn ... https://t.co/H73CU2AB0f
Literally bumped into Sam Shepard many years ago, both of us on our way to see Pillow Man on Broadway. We had a great chat/walk. #hero RIP
R.I.P. Sam Shepard - cowboy poet dramatist of the American family shadow. A legend.
I had the privilege of working with Sam Shepard when I was very young. I remember a very giving a generous man. Sad… https://t.co/5jobMhudTe
Sam Shepard has long been a hero of mine. A versatile artist with an unflinching style entirely his own. A renegade renaissance man. RIP.
And now Sam Shepard https://t.co/vF85U6hNWM
#SamShepard 's Lie of the Mind changed my life. An American hero of the arts, he is irreplaceable. #RIPSamShepard
Paul just said "He left us a lot" about Sam Shepard. He's right. 🖤
Wrote my college essay about a production of Savage Love I did in my backyard. Goodbye Sam Shepard. You left your m… https://t.co/Ol8a0Lcl5b
Rest with the angels, Sam Shepard. My condolences to all that loved him. https://t.co/EmkNymyohG
Sam Shepard, Patti Smith, NYC, 1971 https://t.co/2czI5o5sTE
RIP Sam Shepard. A true hero is gone. I'll always be thankful for his reality, his honesty, his art. Condolences to… https://t.co/2YUcekTgk7
"When you hit a wall — of your own imagined limitations — just kick it in." Sam Shepard was a brilliant artist who… https://t.co/0zUAZ0mBUX
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"We lost one of the great ones. Great writer, great mind," he said, still unpacking the news. "Alright, see you in the next one, Sam."
Shepard was one of the leading figures in the Off-Off Broadway movement, but his breakout film role came in Terrence Malick's 1978 film "Days of Heaven," where he starred opposite Richard Gere and Brooke Adams. He was nominated for an Oscar from his work in"The Right Stuff," and most recently appeared in the Netflix series "Bloodline."
Shepard is survived by his children, Jesse, Hannah, and Walker Shepard; and his sisters, Sandy and Roxanne Rogers.
Jessica Lange and Sam Shepherd (Photo by Ron Galella/WireImage)
Sam Shepard and Jessica Lange (Photo by Ron Galella/WireImage)
Sam Shepherd and Jessica Lange (Photo by Ron Galella/WireImage)
Sam Shepard during 'The Handmaid's Tale' L.A. Premiere Party at Jade West Chinese Restaurant in Los Angeles, California, United States. (Photo by Ron Galella/WireImage)
Jessica Lange and Sam Shepard (Photo by Ron Galella/WireImage)
LOS ANGELES, CA - JUNE 21: Actors Morgan Freeman (L), James Garner and Sam Shepard talk at the after-party for premiere of New Lines' 'The Notebook' at the W Hotel on June 21, 2004 in Los Angeles, California. (Photo by Kevin Winter/Getty Images)
Sam Shepard in a stare in a scene from the film 'Black Hawk Down', 2001. (Photo by Revolution Studios/Getty Images)
Sam Shepard during 'The Notebook' - Los Angeles Premiere - Arrivals at Mann Village Theatre in Westwood, California, United States. (Photo by SGranitz/WireImage)
NEW YORK - NOVEMBER 16: (U.S. TABS AND HOLLYWOOD REPORTER OUT) Actor/writer Sam Shepard attends the opening night of 'The God of Hell' after party at Ramscale November 16, 2004 in New York City. (Photo by Paul Hawthorne/Getty Images)
CANNES, France: (From L) US actors Gabriel Mann, Fairuza Bank and Sam Shepard, Canadian actress Sarah Polley and German director Wim Wenders pose during a photo call for their film 'Dont' Come Knocking', 19 May 2005 at the 58th edition of the Cannes International Film Festival. The film is in competition for the Festival's top prize, the Palme d'Or. The Cannes film festival, the world's top showcase of cinema, started 11 May with a slew of veteran auteurs lining up for the prestigious Palme d'Or prize, and Hollywood muscling in to promote this year's blockbusters. AFP PHOTO PASCAL GUYOT (Photo credit should read PASCAL GUYOT/AFP/Getty Images)
Dallas Roberts and Sam Shepard during Sam Shepard Returns To The Stage After 31 Years Absence In 'A Number' at NYTW Theater in New York City, New York, United States. (Photo by Bruce Glikas/FilmMagic)
CANNES, France: US actor Sam Shepard poses as he arrives for the screening of German director Wim Wenders' film 'Don't Come Knocking', 19 May 2005 at the 58th edition of the Cannes International Film Festival. The film is in competition for the Festival's top prize, the Palme d'Or. The Cannes film festival, the world's top showcase of cinema, started 11 May with a slew of veteran auteurs lining up for the prestigious Palme d'Or prize, and Hollywood muscling in to promote this year's blockbusters. AFP PHOTO FRANCOIS GUILLOT (Photo credit should read FRANCOIS GUILLOT/AFP/Getty Images)
CANNES, FRANCE - MAY 20: Actor Sam Shepard poses for a portrait while promoting the film 'Don't Come Knocking' at the 58th International Cannes Film Festival May 20, 2005 in Cannes, France. (Photo by Carlo Allegri/Getty Images)
FRANCE - MAY 19: 58th Cannes Film Festival: Stairs of 'Free Zone' In Cannes, France On May 19, 2005-Sam Shepard. (Photo by Pool BENAINOUS/CATARINA/LEGRAND/Gamma-Rapho via Getty Images)
Fairuza Balk and Sam Shepard during 2006 Park City - 'Don't Come Knocking' Dinner in Park City, Utah, United States. (Photo by L. Busacca/WireImage)
Sam Shepard (Photo by J. Vespa/WireImage)
Jessica Lange and Sam Shepard during Jessica Lange Honored by the Film Society of Lincoln Center - April 17, 2006 at Avery Fisher Hall in New York City, New York, United States. (Photo by Carley Margolis/FilmMagic)
NEW YORK - APRIL 26: Director Sam Shepard and Jessica Lange attend the premiere of 'Walker Payne' during the 5th Annual Tribeca Film Festival on April 26, 2006 in New York City. (Photo by Thos Robinson/Getty Images for TFF)
Sam Shepard and Jessica Lange during Wynn, Place and Show - Wynn Handman Gala at The Hudson Theatre in New York City, New York, United States. (Photo by Theo Wargo/WireImage)
US actor Sam Shepard adjusts his sunglasses as he arrives for the screening of the movie 'The Assasination of Jessie James by the coward Robert Ford' during the 64th Venice International Film Festival at Venice Lido 02 September 2007. 'The Assasination of Jessie James by the coward Robert Ford' is presented in competition for the Golden Lion Award. AFP PHOTO / ALBERTO PIZZOLI (Photo credit should read ALBERTO PIZZOLI/AFP/Getty Images)
(L-R) Actors Sam Shepard, Brad Pitt and Casey Affleck at the photocall of the film 'The Assassination of Jesse James' by Coward Robert Ford, at the 64th Venice Film Festival. Photographers protested as Pitt attended the photocall entirely wearing sponsored sunglasses and refused to take them off. As result, the photocall was stopped and the cast left the area. (Photo by Alessandra Benedetti/Corbis via Getty Images)
NEW YORK - MAY 29: Actor Sam Shepard recites a short story at 'Toil and Trouble . . Stories of Experiments Gone Wrong' at the World Science Festival held at The Moth at Symphony Space on May 29, 2008 in New York City. (Photo by Amy Sussman/Getty Images for World Science Festival)
TAORMINA, ITALY - JUNE 20: Jessica Lange and Sam Shepard attend a Taormina Art Award during Taormina Film Fest on June 20, 2009 in Taormina, Italy. (Photo by Maurizio Lagana/WireImage)
SANTIAGO BAEZ/ï¿½2009 RAMEY PHOTO NO SPAIN/ NO ITALY/ NO RUSSIA New York, Sep 02 2009 Actor SAM SHEPARD and wife JESSICA LANGE showed their affection while walking around the West Village, NYC. PGsb68 (Photo by Philip Ramey/Corbis via Getty Images)
NEW YORK, NY - SEPTEMBER 29: Actor Sam Shepard attends the premiere of 'Blackthorn' at Cinema 2 on September 29, 2011 in New York City. (Photo by Michael Stewart/WireImage)
PASADENA, CA - JANUARY 09: Actor Sam Shepard speaks onstage during the 'Discovery Channel - Klondike' panel discussion at the Discovery Communications portion of the 2014 Winter Television Critics Association tour at the Langham Hotel on January 9, 2014 in Pasadena, California. (Photo by Frederick M. Brown/Getty Images)
NEW YORK, NY - AUGUST 27: Sam Shepard attends the 'Heartless' opening night party at Signature Theatre Company?s Pershing Square Signature Center on August 27, 2012 in New York City. (Photo by Paul Zimmerman/WireImage)
PARK CITY, UT - JANUARY 18: Actor Sam Shepard poses for a portrait during the 2014 Sundance Film Festival at the Getty Images Portrait Studio at the Village At The Lift Presented By McDonald's McCafe on January 18, 2014 in Park City, Utah. (Photo by Larry Busacca/Getty Images)
PARK CITY, UT - JANUARY 18: Actor Sam Shepard attends The 10th Anniversary LG Music Lodge At Sundance With Elio Motors And Tervis on January 18, 2014 in Park City, Utah. (Photo by Clayton Chase/Getty Images for LG Music Lodge)
PARK CITY, UT - JANUARY 18: Kirt Russell, Sam Shepard, Goldie Hawn and Don Johnson attend the 'Cold in July' Dinner and Party hosted by The Snow Lodge x Eveleigh on January 18, 2014 in Park City, Utah. (Photo by Craig Barritt/Getty Images for Snowlodge)
NEW YORK, NY - OCTOBER 08: (EXCLUSIVE ACCESS) Playwright Sam Shepard poses at The Opening Night for the MTC production of Sam Shepard's 'Fool For Love' on Broadway at Urbo NYC on October 8, 2015 in New York City. (Photo by Bruce Glikas/FilmMagic)