Falling in love with a television show is easy for most people. But falling in love with a television show that spans decades is like finding a needle in a haystack. And, with even more content out there than ever before, the odds of a television show lasting more than a few seasons is slim to none.
However, there are a handful of primetime television shows that have managed to do the impossible and thrive for decades, sometimes even multiple decades. From crime and medical shows to TV classics and animated favorites, there doesn't seem to be any one type of show in particular that goes the distance, it all just depends on what happens to click with viewers. As a note, this list focuses specifically on network American television and doesn't include shows on cable or that originated in other countries.
Updated on May 2nd, 2021 by Kristen Palamara: With so many new shows and pilots being greenlit it's difficult for primetime shows to stand out amongst the lineup of new shows let alone run for dozens of seasons, but these shows have managed to do just that. These primetime TV shows have the most seasons and are the longest-running shows as each one of them aired new episodes for more than a decade and consistently kept enough of a fanbase to stay on the air for so long and still be successful up until the end.
Bonanza - 14 Seasons
Bonanza was a Western that first aired in 1959 and had its final episode in 1973 with over 400 episodes over its 14 seasons. The series followed a family of ranchers, Ben Cartwright and his 3 sons, trying to survive during and after the U.S. Civil War.
Fans tuned in every week for over a decade to watch the Cartwright family work on their land, called the Ponderosa, and live their more personal lives outside of work on the ranch as well.
Criminal Minds - 15 Seasons
Criminal Minds was an intriguing police procedural program with a twist as it focused on the FBI profiling team that used more psychological approaches to solving their crimes as they created a profile for people who might have committed heinous crimes and worked from there.
It was a gritty series that alleviated its serious moments with more comedic ones and had a large cast of characters with unique personalities. This balance made the series popular and kept it going for 15 seasons.
The Jack Benny Program - 15 Seasons
The Jack Benny Program was similar to a sketch show as host and comedian Jack Benny would welcome new guests every week and provide laughs during their weekly primetime programming.
The series ran for over 300 episodes in its 15 seasons starting in 1932 and ending in 1965. Fans were obviously tuning in to the program with it lasting over 30 years on the air and one of the first weekly television programs for people to view at home.
ER - 15 Seasons
Grey's Anatomy to be as popular as they are. ER ran for a total of 15 seasons and focused on several doctors, nurses, and other hospital employees working their jobs and living their lives outside of work.
Fans continued to tune into the show even as characters left and new characters were introduced and ER proved that the medical drama was a force to be reckoned with.
Supernatural - 15 Seasons
Supernatural ran for 15 years and 15 seasons on the CW as one of the channel's most popular and longest-running shows. The series followed the Winchester brothers, Sam and Dean, as they traveled the U.S., hunted monsters, and saved people.
Fans continued to tune into the series to see the character building of both the Winchester brothers and everyone they interacted with, human or supernatural creatures, including recurring fan-favorite character Castiel.
CSI: Crime Scene Investigation - 15 Seasons
CBS's procedural forensics drama series CSI: Crime Scene Investigation premiered in October 2000 and ended its fifteen-year run in September 2015.
The series was so successful it helped launched a massively popular franchise which now includes three other television series, in addition to making the leap to video games and other forms of media. During its historic run, the series was nominated for various Emmys and other awards, earning it critical acclaim.
Grey's Anatomy - 16 Seasons
Grey's Anatomy has dethroned ER as being the longest-running primetime medical drama series in September 2019 when the sixteenth season began airing on ABC.
The Shonda Rhimes-created drama first premiered in March of 2005 and since then has become a cultural phenomenon. Over the years there has been a revolving cast of characters— with several leaving over creative differences— but one thing that has remained the same is that the series promises to bring the drama every episode.
American Dad! - 17 Seasons
Seth MacFarlane-created animated series to earn a spot on the list of longest-running primetime television shows of all time. The series follows Stan Smith, a homeland security CIA agent, who must juggle his stressful job with his eccentric family which includes Roger, an alien who escaped Area 51.
American Dad first started airing on renewed for two more seasons which will bring it to 19.
NCIS - 17 Seasons
CBS's police procedural NCIS also makes the list of longest-running primetime television shows with seventeen current seasons and an eighteenth set to star premiering in the next few weeks.
NCIS centers on Leroy Jethro Gibbs (Mark Harmon) and his team of Naval Criminal Investigative Service Special Agents as they investigate primes that deal with the Navy and Marine Corps. Like CSI, NCIS has created several successful spins off, turning it into a franchise.
Family Guy - 19 Seasons
Seth MacFarlane's longest-running animated show is none other than Family Guy. The animated sitcom first aired on Fox in January 1999 and has continued to call Fox home for the last nineteen seasons.
Family Guy is interesting because it was actually canceled by Fox after its third season. However, strong DVD sales and the success of reruns on Adult Swim inspired Fox to reverse its cancellation order. Since then, the series has continued to be a top performer for Fox and one that the network probably wouldn't be looking to cancel (again) anytime soon— though its future is somewhat uncertain given MacFarlane g a deal with NBCUniversal earlier this year.