Series 1 (2001–02)

All three finalists of the inaugural series released debut albums, but while Rosa (accompanied by some fellow contenders as backing singers) scored seventh place in the Eurovision Song Contest 2002 with the song "Europe's Living a Celebration", and had notable success with her albums, it was Bisbal who went on to international success, even winning a Latin Grammy Award for Best Newcomer for his album Corazón Latino.

Other participants of this first edition (Chenoa, Nuria Fergó and Manu Tenorio) also launched successful solo careers. In addition, Gisela was hired by Disney Spain and started a career in musical theater; and represented Andorra in the Eurovision Song Contest 2008.

Series 2 (2002–03)

The second series of Operación Triunfo became an anomaly in the category of popular reality TV music shows. First of all, the winner had very little success after the show. Second of all, many contestants who did not do well had massive success across Europe and Latin America, not just in Spain:

Beth was chosen to represent Spain in the Eurovision Song Contest 2003. She scored 8th place with the song "Dime".

The first person out of the show, Mai Meneses, rose to prominence in 2006 when herself and a childhood friend formed the band Nena Daconte. They released an album, He Perdido Los Zapatos, which was highly praised by critics. The album sold over 200,000 copies in Spain alone, an amazing feat as an average album to get to number 1 in Spain needs around 20,000 sales.

Vega, who came 9th, managed to release the best selling single of 2003 in Spain with her own composition, "iGrita!", with over one million copies sold.

Series 3 (2003–04)

Series three runner-up Ramón was chosen to represent Spain in the Eurovision Song Contest 2004. He scored 10th place with the song "Para llenarme de ti".

This was the last series aired by TVE until 2017, and the one with the lowest ratings until 2011.

Series 4 (2005)

TVE refused a fourth series, choosing to select its Eurovision Song Contest entry using a multi-artist national final. The show was then offered to Telecinco, who bought its rights. This fourth series started airing in June 2005 and got better ratings than the third one, but it never reached the results that the first series achieved. Runner-up Soraya Arnelas would represent Spain at the Eurovision Song Contest 2009 and sixth-placed Edurne would represent Spain at the Eurovision Song Contest 2015.

Series 5 (2006–07)

Telecinco announced in May 2006 that the fifth series of the program was to be released in October 2006.

In July, 25 Telecinco aired a special show titled Operación Triunfo 2006: Otra Vez en Marcha. In this show some former OT artists (among them, Rosa, Soraya Arnelas, Sergio Rivero, Natalia, Beth) performed and the new selection of contestants was introduced.

The fifth series started on Sunday 8 October 2006 with 18 finalists, but two finalists had to leave and they didn't enter the academy. It created some controversy as one of the first two people out that night was the first black person, Claritzel, ever to be on the show (she had to pull out of the previous year's show). She had to leave the show because of a heart intervention.

Series 6 (2008)

Castings started in Barcelona for the new series on 18 February 2008. The sixth series began on 8 April 2008, with 18 candidates to enter the academy (two of them didn't). This series has been the most controversial because many critics pointed that the series centered more on the reality show aspect than on the contestants' performing talent. Runner-up Pablo López went on to launch a successful recording career in 2014.

Series 7 (2009)

The castings were made in March and April 2009 in all Spain. The first gala from OT 2009 was televised on 29 April 2009. Once again, Risto Mejide was a part of the jury panel, along with Noemí Galera, Coco Comín and Ramoncín.

Series 8 (2011)

This was the last series aired by Telecinco. The show was cancelled after 35 days due to poor ratings. It ended with a rushed finale featuring contestants from previous series. Despite the low ratings, fans of the show made the Twitter hashtag #VivaOT, which went on to be the highest trending topic during the airing of the finale.^[8]

Series 9 (2017–18)

Six years after the show was discontinued and thirteen years after it last aired on TVE, RTVE approved to revive the contest. The total cost of the new series was €10,2 million. Casting auditions for the ninth series were held from 14 June 2017 to 18 July 2017 in Barcelona, Las Palmas, Palma, Valencia, Santiago de Compostela, Bilbao, Granada, Seville, and Madrid. The minimum age to compete was raised to 18.^[9] On 18 July 2017, Noemí Galera, a member of the jury panel on previous series, was announced as the new "headmaster" of the Academy.^[10] On 28 August 2017, it was revealed that the jury panel would consists of singer, songwriter and producer Mónica Naranjo, marketing director Joe Pérez-Orive and music executive and producer Manuel Martos, who would be accompanied every week by a fourth guest juror.^[11] On 30 August 2017, Roberto Leal was announced as the new host.^[12] The series premiered on 23 October 2017. The final took place on 5 February 2018, and Amaia Romero was announced the winner.^[13] In addition, Amaia and Alfred were selected to represent Spain in the Eurovision Song Contest 2018 with "Tu canción", and finished in twenty-third place out of 26 countries.

Series 10 (2018)

On 28 February 2018, RTVE's Governing Board approved the renewal of Operación Triunfo for a tenth series.^[2] Casting auditions for the tenth series were held from 30 May 2018 to 10 July 2018 in Barcelona, Alicante, Valencia, Majorca, San Sebastián, Vigo, Tenerife, Málaga, Seville and Madrid.^[14] The series premiered on 19 September 2018 and ended on 19 December 2018.

The 18 contestants that appeared on the introduction live show or Gala 0 were announced on 14 September 2018.^[15][16]

As in the previous season, the series served as the platform to select the Spanish entry at the Eurovision Song Contest 2019.^[17][18] A special live show was held on 20 January 2019 to select the Spanish entrant and song for Eurovision.^[19]

Series 11 (2020)

In January 2019, TVE confirmed an eleventh series.^[20][21][22] Casting auditions for the eleventh series were held from 7 October 2019 to 6 November 2019 in Barcelona, Las Palmas, Valencia, Palma, Málaga, Seville, Bilbao, Santiago de Compostela and Madrid.^[23] The series premiered on 12 January 2020.

Series 12 (2023–24)

Three years after it last aired in TVE, Amazon Prime Video acquired the rights to air the series.^[6] On 27 May 2023, series one contestant Chenoa was announced as the host.^[24] Casting auditions were held from 3 July 2023 to 19 September 2023 in Barcelona, Zaragoza, Santiago de Compostela, Bilbao, Valencia, Las Palmas, Málaga, Seville and Madrid.^[25] The series premiered on 20 November 2023.^[26]