As founding Executive Vice President and Executive Producer of Outside Television,^[16] Les Guthman produced 28 feature-length expedition, adventure and environmental documentaries, including Michael Brown's Farther Than the Eye Can See, which was nominated for two primetime Emmy Awards in 2004,^[17] the awards for Outstanding Sports Documentary and Outstanding Sports Cinematography. Farther Than the Eye Can See,^[18] the film of blind climber Erik Weihenmayer’s renowned ascent of Mount Everest, won 18 international film festival awards.^[19] Altogether, there have been 223 film festival screenings of Guthman's films since 2002 and they have won 41 film festival awards.

Outside was the second major American magazine that Guthman brought to national television. In 1991, he created and produced the Discover Magazine series at the Walt Disney Company, based on Discover magazine. He produced the Discover Magazine TV series for two seasons on The Disney Channel,^[20][21] and then, working with Disney President and CEO Frank Wells, moved it to the Discovery Channel, where it became a signature series. At the same time, he developed an unproduced series with HBO based on a comedian's view of science.

One of the other highlights of Guthman's leadership of Outside Television was the expedition and expedition film, Into the Tsangpo Gorge,^[22] which he produced and also co-wrote with director Scott Lindgren. The expedition achieved the epic first whitewater descent of the “Everest of rivers," through the 18,000-ft.-deep Tsangpo Gorge (Yarlung Tsangpo Grand Canyon) in Tibet and was recognized by The Explorers Club as one of the most accomplished expeditions of modern times.^[23] Into the Tsangpo Gorge aired on NBC Sports in May 2002.

Into the Tsangpo Gorge and Farther Than the Eye Can See, along with his production, Into the Thunder Dragon,^[24] by filmmaker Sean White, were honored by Men’s Journal magazine as three of the 20 Top Adventure Films of All Time.

His Outside Television production, In the Shadow of the Condor^[25] won the 2001 Teddy Award^[26] for Best Conservation Film, named in honor of President Theodore Roosevelt. His production The Teachings of Moises Chavez^[27] was runner-up for the same award in 2002.

He co-created and produced the CableAce Award-nominated science series 21st Century, which included the last interview^[28] with Dr. Jonas Salk, discoverer of the polio vaccine.^[29] 21st Century was co-created and hosted by NPR and KCRW host Warren Olney.

Guthman has directed 13 documentaries, including Messner (2002),^[30] the first documentary about Reinhold Messner, world's greatest mountain climber, since Werner Herzog’s The Dark Glow of the Mountains in 1984. Messner was an Opening Night selection of the Mountainfilm in Telluride festival in 2004. He also made two highly regarded environmental films: The Hudson Riverkeepers (1998)^[31][32] and The Waterkeepers (2000).^[33] In 2008, on the tenth anniversary of The Hudson Riverkeepers, Guthman re-edited the two films into one feature-length documentary under the title, The Waterkeepers. It premiered at the Environmental Film Festival in the Nation's Capital and was released on iTunes and Amazon Video.^[34] He has written 15 documentaries and edited 12.^[35]

Churning the Sea of Time: A Journey Up the Mekong to Angkor,^[36] premiered at Lincoln Center in April 2006. It was an official selection of the Museum of Modern Art's "Directors Fortnight Expanded"^[37] in 2007 and was shown at the Royal Geographical Society in London, the Smithsonian in Washington, DC; and the Asia Society in New York, among other featured screenings.

Guthman's 2009 feature documentary, Skiing Everest (film),^[38] features the handful of skiers worldwide who climb Mount Everest and other 8,000-meter peaks alpine style (without using supplemental oxygen, or hiring porters and guides), and click into their skis. Filmed around the world, it includes skiers Mike Marolt, who was also director of photography, Steve Marolt, Hans Kammerlander, Chris Davenport, Laura Bokas, Mark Newcomb and Fredrik Ericsson.^[39] Skiing Everest was licensed by ESPN in 2011 for broadcast in the United States and Europe. It debuted on ESPN Classic in November 2011 with six primetime broadcasts over the weekend of November 18–20.^[40] Skiing Everest (film) was converted from 2D to 3D in 2012 by Blue Hemisphere 3D.

His 2011 documentary Saturn's Embrace^[41] brings to the screen the Cassini-Huygens mission's exploration of Saturn and its moons through Cassini's unsurpassed photographs and radar images; and explores the stunning discovery of salt water, with its possibility of primitive life, on the moon Enceladus. The film features, and is written and co-produced by, Dr. Carolyn Porco, head of the Cassini-Huygens digital imaging team, and includes commentary by evolutionary biologist and author Richard Dawkins.

In 1996, Les Guthman made Corwin,^[42] a feature-length documentary about Norman Corwin, the legendary writer, producer and director during the Golden Age of Radio. Corwin aired on PBS,^[43] having been licensed by PBS stations WNET in 1996 and then by KCET in 1999. Actor Charles Laughton, in the early 1940s, is quoted in the film as saying, "There is no actor in Hollywood or on Broadway, who would not drop what he is doing to be in one of Norman Corwin's radio plays. We all look up to him as a writer of the highest caliber and one of the most important writers in America today." KCET in Los Angeles re-broadcast "Corwin" in October 2011 as a memorial tribute when Mr. Corwin died at the age of 101.^[44]

In 1999, Guthman won the National Academy of Sciences nationwide competition to select the best new series concept in science television, which resulted in his film, Three Nights at the Keck, hosted by actor John Lithgow.^[45]

In 1989, Guthman brought the annual Robert F. Kennedy Human Rights Award ceremony to PBS in a primetime broadcast^[46] hosted by Tom Brokaw and featuring a human rights address by Sen. Ted Kennedy and a keynote speech by Polish Solidarity leader Lech Wałęsa. The ceremony honored the Tienanmen Square protests of 1989 and the fall of the Berlin Wall the same year. The Robert F. Kennedy Human Rights Award was given to Chinese dissident Fang Lizhi, who was being protected inside the U.S. Embassy in Beijing at the time of the broadcast.

Les Guthman's credits include almost a decade at NBC News in New York, where he was a producer and writer for Tom Brokaw, as well as senior political writer and Manager of Election Analysis.

He was Story Editor and Story Consultant on Visions, the Peabody Award-winning landmark PBS series, which commissioned 80 scripts and produced 40 feature-length independent films and television stage productions over four seasons at KCET in Los Angeles.^[47] One of its films, Alambrista,^[48] won the Camera d'Or award at the 1978 Cannes Film Festival.^[49] Michael Arlen, the television critic for The New Yorker, wrote in his review of Visions, "One might say that, halfway through its first year, Visions is already the most interesting and original regular American dramatic program that can be found anywhere on American television."

Visions lasted four seasons, after which Les Guthman joined Norman Lear’s Tandem Productions, where he produced and co-wrote two feature film projects that he had developed during the final year of Visions. One was a collaboration with director St. Clair Bourne and playwright Ron Milner for a feature film about the civil rights era confrontation between young black voting rights activists and the Ku Klux Klan in Bogalusa, Louisiana.

Guthman's other films are Paragliding Across America (2001),^[50] the expedition of world-record-holding paraglider Will Gadd to become the first to paraglide across the United States; Marathon of the Sands (2000),^[51] the world's most grueling ultra-marathon competition in the Moroccan Sahara; Eco-Sanctuary Belize (2001)^[52] and Ten Adventures of a Lifetime (2004).^[53]

In 2004, he created XPLR Productions, based in New York. XPLR Productions partnered with Snagfilms in 2008 to create the webcasting channel XPLR for adventure, environmental and science documentaries, including many of the films listed above. Selected XPLR-produced and distributed films also stream on Amazon Video,^[12] Hulu,^[54] Roku,^[55] EPIX,^[56] Comcast Xfinity,^[57] Verizon FIOS,^[58] Xbox,^[59] Redbox Instant,^[60] Google Television and Sony,^[61] Panasonic and Visio televisions, and are available on mobile devices and tablets through the Snagfilms and Amazon Video apps.

On the fifth anniversary of the historic LIGO discovery, Guthman published A Discovery That Shook the World, an ebook based on his eight-part video series of the same name.^[62]

Previously, he had edited three books by three-time Pulitzer Prize winning editorial cartoonist Paul Conrad: The King and Us,^[63] Pro and Conrad,^[64] and Paul Conrad: Drawing the Line.^[65]

A member of the Explorers Club in New York since 2000, he was head of the Explorers Club Film Festival in 2008,^[66] and 2015.^[67] He chaired its Rolex Artist-in-Exploration competition from 2013 to 2016^[68] and the club's $100,000 World Exploration Challenge grant competition, sponsored by the Mamont Foundation.^[69] He was inducted as a Fellow of the Royal Canadian Geographical Society in 2017.

• Les Guthman at IMDb
• les.guthman.com
• "A Discovery That Shook the World" ebook