Early on, seasons generally had 15-16 episodes, each focusing on such topics as natural disasters, technology, war, the old West, civil rights, crime, politics, and biographies of American icons, among other things (Presidential biographies in particular are this program's claim to fame, with the three-part "Nixon" being the first and the four-part "LBJ" receiving some of the greatest critical acclaim of them all). More recent seasons have included as few as two or as many as five or six new episodes, with repeats taking up the rest of the season. Until 2007, seasons started in the fall; beginning with the 20th season in 2008, new seasons commenced in the winter (the last season to premiere in the fall was the 23rd season, in 2010). Originally broadcast on Mondays, the program was moved to Tuesdays beginning with its 24th season in 2012, as part of a larger drive towards brand unity at PBS.
For the first several years, the program was hosted by historian David McCullough, best known for his role as narrator of Ken Burns' The Civil War. McCullough narrated several episodes himself, including "The Hurricane of '38" (1993) and "Abraham and Mary Lincoln: A House Divided" (2001). The program no longer has a host, but new episodes are typically narrated by actors Oliver Platt and Michael Murphy.
This documentary series features examples of:
- Cassandra Truth: Turns up in many episodes.
- "The Donner Party": Mountain man James Clyman told James Reed not to take Hastings' Cutoff to California, because Clyman knew it to be a dangerous route. Reed brushed off Clyman's advice. The end result: Reed's party ended up trapped for the winter in the California mountains and more than half of them perished.
- "The Crash of 1929": In the 1920s, economist Roger Babson railed against the unregulated stock market, cautioning that it would result in a crash, and was ridiculed for lack of confidence in the American economic system. In 1929, he was proven right.
- Desecrating the Dead: "John Brown's Holy War" relates the tale of one of Brown's followers (an African-American ex-slave) whose corpse was brutalized after he was killed, including having his ears cut off for souvenirs. Another of Brown's followers had his dead body thrown into a river where angry townspeople used it for target practice.
- Foregone Conclusion: "Influenza 1918": A nurse who worked in an Army hospital in Chicago during the pandemic recalled that new patients had their bodies wrapped in winding sheets and toe tags placed on their feet while they were still alive, because of the likelihood that they would die. Another woman, who came down with a severe case of influenza as an infant, relates a story about her mother being told by a doctor not to feed her anymore, because her recovery was unlikely. In this case, the trope is averted, because she survived to tell the story in her old age.
- Karma Houdini: Countless examples. Some of the most egregious ones include:
- "My Lai": Lt. William Calley ended up serving only 3 1/2 years house arrest for the cold-blooded massacre of over 300 innocent Vietnamese civilians in 1968. No one else served one second of time.
- "The Murder of Emmett Till": J.W. Milam and Roy Bryant were acquitted of the murder of the African-American teenager (who had been falsely accused of sexually harassing Bryant's wife) by an all-white jury. Months later, they admitted to the murder in a national magazine, but could not be retried due to double jeopardy laws. No one ever served a day in jail for Till's murder.
- "The Massie Affair" aka "The Island Murder": In 1931, Grace Fortescue, a New York socialite, was put on trial for the cold-blooded murder of a young Hawaiian man who was falsely accused of assaulting and raping her daughter. She was initially sentenced to ten years in prison, but the judge bowed to pressure from racist whites and commuted her sentence to one hour. In a true case of Karma Houdini, Fortescue was hailed as a hero who "avenged her daughter's honor" (despite evidence showing that no rape ever occurred) and lived the rest of her life in comfort. On the other hand, in a case of Laser-Guided Karma, her daughter ended up living a very unhappy existence and attempting suicide several times, finally succeeding with an overdose of pills.
- The Ken Burns Effect: Ken Burns himself has contributed several installments to the series, including Empire of the Air, a look at the early days of radio in America. Likewise Ken's brother Ric, including an award-winning 1992 profile of the Donner Party.
- Long-Runners: For over 30 seasons, this has been PBS's flagship American history series.
- Never My Fault:
- "The Hurricane of '38": After a Category 3 hurricane catches Long Island and New England by surprise and kills roughly 700 people in September 1938, the U.S. Weather Bureau, whose forecasts had given no mention of a hurricane until it was too late due to bungled forecasting, denies any responsibility, claiming New Englanders wouldn't have heeded storm warnings because they were "not properly hurricane-minded."
- "Into the Amazon": During the Roosevelt-Rondon Expedition in the Amazon rain forest in 1914, Theodore Roosevelt's son Kermit ignores Col. Candido Rondon's warnings to not try to paddle through rapids on the River of Doubt (now Rio Roosevelt). The result: Kermit's canoe gets caught in a whirlpool and thrown over a waterfall, one of the two paddlers drowns, and Kermit barely makes it out alive himself. Rondon is furious, but the Roosevelts deny responsibility, blaming the river for the paddler's death.
- Precision F-Strike:
- The two-part biography "Walt Disney" includes a speech from Uncle Walt which includes a few uses of "damn". Particularly in the '40s, when the only mainstream Hollywood picture to use that word was Gone with the Wind (and even then just because the original novel also had Rhett Butler's famous parting words to Scarlett O'Hara as "My dear, I don't give a damn"), that was quite shocking.
- This series is itself known for getting away with stronger language than PBS is typically comfortable with broadcasting. The Presidential biographies in particular have a few instances of "shit" (including at least one "bullshit") that were heard unbleeped even in the 2016 rebroadcasts, during a time when British drama on the network didn't get to go much farther than "bitch" (which guarantees at least a TV-PG-L rating), with the only known program to score an L subrating for its TV-14 rating using the word "dick" uncensored.
- Documentaries dealing with the African-American civil rights struggles of the 1950s and '60s are also typically broadcast with the "n"-word uncensored (not "Negro"; the other one), though it's almost always heard in archival footage.
- Theme Tune: The series' theme music has changed several times over the years but has always been instrumental, with the exception of the 2009 and 2010 seasons, which used an edited version of The Chambers Brothers' psychedelic-rock classic "Time Has Come Today" as an actual Theme Tune.
- Title Sequence Replacement:
- Very often happens during rebroadcasts in the middle of a newer season, especially if the title sequence for the series itself has been updated.
- Several episodes, including "LBJ", have had their titles replaced entirely in newer broadcasts. "Nixon", on the other hand, subverts this by retaining the original episode titles at the start of each part, even in the 2016 rebroadcast.
- Very Special Episode:
- Reruns of past episodes with relevance to a current trend or news development are common. For example, the series premiere, "The Great San Francisco Earthquake", was rebroadcast the week after San Francisco was rocked by another major earthquake in 1989. More recently, past episodes about the Spanish Influenza of 1918 and the struggle to eradicate polio were rerun in 2020 during the global COVID-19 pandemic.
- So are new episodes commemorating an anniversary of an important historical event, such as 2019's three-parter "Chasing the Moon," which coincided with the 50th anniversary of the Apollo 11 mission.
- Presidential biographies tend to get this treatment during election years, with the first known such event being a rebroadcast of "Nixon" during the fifth season.
- In addition, some PBS documentary mini-series produced before 1988, such as Vietnam: A Television History (1983) and Eyes on the Prize: America's Civil Rights Years (1987), have been rerun and also released on DVD under the American Experience banner. So have independent films such as the previously Oscar-winning The Johnstown Flood (1989), broadcast in 1990 with some new footage added.