Harry O, sometimes spelled Harry-O, is an American private detective series that aired for two seasons on ABC from 1974 to 1976. The series starred David Janssen, and Jerry Thorpe was executive producer. Harry O followed the broadcast of two pilot films: firstly Such Dust as Dreams Are Made On (which aired on March 11, 1973) and secondly (with noticeable retooling) Smile Jenny, You're Dead (which aired on February 3, 1974), both starring Janssen.^[1]

David Janssen starred as the title character Harry Orwell, a San Diego cop forced into retirement when he is shot in the back. To support himself, he sets up a private investigation practice out of his beach house on Coronado Island, in San Diego. Henry Darrow, (formerly of the 1967-71 NBC hit Western series, The High Chaparral), originally starred as Lt. Manny Quinlan, his friend and police contact.

For the second half of the first season, the series was retooled, with the location of the series shifted to Los Angeles, California, due to the high production costs of filming in and around San Diego.^[2] The retooling consisted of more than just a location change; a revised theme song and incidental music were composed and new supporting characters were added, notably the irascible Lt. Trench of the Santa Monica Police Department, who became Orwell's new foil/contact. (Henry Darrow's character, Lt. Quinlan, was killed off in a crossover episode.) Most noticeably, a lighter tone for the scripts and acting was adopted. Harry still lived in a beach cottage−this time somewhere along the Pacific Coast Highway between Malibu and Santa Monica. In "Reflections", episode five of season two, he gave the address as "1101 Coast Road" (this beach location was the same location used for the second pilot movie).

The second season had a further reworking of the opening credits and theme song, and recurring characters were added. Anthony Zerbe, who played Lt. Trench, won a Primetime Emmy Award for his role on the series.

Recurring characters included Farrah Fawcett-Majors, as Harry's attractive next-door neighbor and sometime girlfriend Sue Ingram/Ingham; Paul Tulley as Sgt. Roberts, Lt. Trench's assistant; Les Lannom as Lester Hodges, a bumbling private-eye wannabe; Tom Atkins as Sgt. Frank Cole; and Bill Henderson as Spencer Johnson, Harry's frustrated car mechanic.

Harry's small Austin-Healey, which spent almost all of the first season in non-running condition, later had more time on the road as the series progressed, though it was never entirely reliable. Also, in the San Diego episodes, the bullet in Harry's back noticeably impeded his ability to get around; by the second season, though the bullet's existence was mentioned in passing, Harry was miraculously able to run, jump, and engage in strenuous physical activity with seemingly no issues.

Ratings for the series were initially fair, and they received a boost after the series was retooled in January 1975. Harry O was picked up for a second season and continued to gain viewership and critical acclaim. Then-ABC president Fred Silverman, though, decided to take the network in a different direction and cancelled the series in favor of Charlie's Angels. Farrah Fawcett-Majors, supporting player to Janssen's Harry O, was selected as one of the three stars of that new series.

The last original episode aired on April 29, 1976.^[3] The series' cancellation greatly disenchanted its star Janssen, who had found and shaped probably his most ideal character ever in Harry Orwell; he thus vowed never again to participate in another television series . He would do so, though, later, in the miniseries Centennial (1978–79).^{[4][circular reference]}

The show was rerun late at night on CBS during 1979-1980. It was run in syndication in the late 1980s on a few stations around the US and had a short-lived run on GoodLife TV Network in the early 2000s. The first pilot movie still receives occasional airings.

The series is occasionally presented in weekend binges on the OTA television network Decades and on weekday afternoons on MeTV+.

On July 11, 2012, Warner Bros. released Harry O: The Complete First Season on DVD in region 1 via their Warner Archive Collection. This is a manufacture-on-demand (MOD) release, available exclusively through Warner's online store and only in the US.^[9] The 6-disc set features all 22 episodes of the season as well as the original pilot tele-film Such Dust as Dreams Are Made On. The second and final season was released by Warner Archive on February 5, 2013.^[10]