It soon exerted a strong influence on radio programmers because of its audience and the amount of Australian content it featured.

Molly Meldrum, the program's talent co-ordinator, began appearing on-air in 1975, presenting the "Humdrum" music news segment and conducting interviews.

Teen-oriented pop music still enjoyed strong popularity during the 1970s, although much of it was sourced from overseas, and the proportion of Australian acts in the charts had hit an all-time low by 1973.

Much of the show's influence derived from its timeslot (Sundays at 6pm) and the fact that each week's show was repeated the following Saturday at 5pm; the series also undoubtedly benefitted hugely from the long-delayed introduction of PAL colour television system in Australia, which was introduced four months after Countdown premiered.

[2] Although it is not widely recognised, Countdown also had a strong international influence, because it was one of the first TV shows in the world to promote the regular use of the music video as a major part of its programming.

Above all, Countdown was crucial to the success of many leading Australian acts, including John Farnham, AC/DC, Olivia Newton-John, INXS, Dragon, Hush, Kylie Minogue, I'm Talking, John Paul Young, Sherbet, Skyhooks, Ted Mulry Gang, Jimmy and the Boys, Marcia Hines, Mark Holden, The Angels, Mondo Rock, Men at Work, Icehouse, Australian Crawl and Mental As Anything.

It was well known that his shaved head was a statement to artists like Midnight Oil, who during their career, and being one of Australia's favourite bands, never appeared on the show due to regarding Countdown as too industry/hit-driven and appealed only to a young teenage audience.

In March 2007, the pay television service Foxtel, and its regional affiliate Austar, began screening hundreds of studio performances from the Countdown era.

A well-known segment of the show's run is an atypical studio interview Meldrum conducted with Prince Charles.

A large number of master videotapes recorded between 1974 and 1978 were later erased and recycled during a management-initiated "economy drive" at the ABC, an action which Meldrum later criticised and said was "unforgivable".

In the book Glad All Over,[11] Michael Shrimpton said at that time the ABC were "run by financial types [who] suddenly discovered that the increase in the purchase of video tapes had roared up 200 percent in 12 months".

Ted Emery and Paul Drane heard about the order, surreptitiously removing as many reels as they could during the middle of the night and hiding them in their cars.

A number of Australian Rules Football Grand Final games,[11] along with episodes of Bellbird and Certain Women, were also erased.

It is the copying of the programs onto this format that has allowed the ABC to re-broadcast episodes of Countdown during its all-night music show, Rage, in place of video clips which would normally air during that timeslot.

Missing-episode enthusiast Troy Walters has a website Turning Back Time: The Hunt For ABC's Countdown, which discusses what has been lost and found.

The duo were fired by the ABC after an unauthorised on-air protest on 22 June 1990 against the policy of not allowing acts to perform live and insisting they mime to backup tracks.

Video clips were generally shown, but memorable appearances live on stage included Poison ("Nothin' but a Good Time"), Faith No More ("Epic"), Kylie Minogue ("Hand on Your Heart" and "Never Too Late"), Jason Donovan ("Sealed with a Kiss"), Collette ("All I Wanna Do Is Dance" and "That's What I Like About You"), Brother Beyond ("He Ain't No Competition"), Indecent Obsession ("Say Goodbye"), Martika ("I Feel The Earth Move"), James Freud ("One Fine Day") and many more.

The hour-long Batdance competition was a high-rating show in November 1989, where Molly Meldrum aided in the judging of the talent from the state finalists.

Countdown, the show that epitomised the pop music scene in Australia for over a decade, celebrated the 40th anniversary of its debut with the release of an anthology album in 2014.

Australian actor Samuel Johnson starred as Meldrum, with Tom O'Sullivan as Shrimpton and T.J. Power as Weekes.

[18] Rage now regularly plays chart hits with a 'Countdown' of the most popular videos from the ARIA singles[19] On 17 September 2017, the ABC commenced airing a retrospective of the show, comprising 13 one hour episodes.