Since his first appearances in "Menuda Noche", a friend of Mateo's family posted in YouTube videos of his performances. Early 2009, when he was ten, he signed a contract with EMI Music Spain and released on 4 December of the same year his debut album, recorded in Madrid, under the title Abraham Mateo It was digitally released on 27 November 2009.Mateo at benefit concert in San Fernando, Cádiz on 17 April 2010
The album, produced by Jacobo Calderon and Jose Luis de la Peña, contains twelve songs, seven of them were composed by Calderon himself and four tracks are covers of popular Latin songs such as Raphael's "Cuando Tu No Estas" ("When You Are Not Here"), Alejandro Sanz's "Los Dos Cogidos de la Mano" ("The Two Holding Hands"), Laura Pausini's "La Soledad" ("La Solitudine/The Loneliness") and Jaci Velasquez's "Imaginame Sin Ti" ("Imagine Me Without You"). The album includes a duet with the French teen singer Caroline Costa, the runner-up in the 2008 edition of the television contest Incroyable Talent, the French version of America's Got Talent. Abraham and Caroline recorded for the album a Spanish version of Badfinger's "Without You", the song has also been covered with great success by Mariah Carey. To promote the album, Mateo has toured through several cities in Spain and performed in many Spanish radio and television shows, including the popular television programs Mas Que Baile, Tu Si Que Vales, The Show of Maria Teresa Campos, and the Christmas Eve Special of the Telecinco channel. He was also invited to perform at the International Carnival Maspalomas in Gran Canaria.
Mateo began to record songs in English during the summer of 2010, performing "I Surrender" by Celine Dion, "I Have Nothing" by Whitney Houston, "Just the Way You Are" by Bruno Mars, "Imagine" by John Lennon, and "Mistletoe" by Justin Bieber. In summer 2011, he released an Italian version of the classical song Adagio by Lara Fabian, hist first song in Italian.Shortly after releasing this song, he was invited to perform at a TV show presented by the Italian singer Rafaela Carra on the Italian channel Canale 5. On 29 November 2011, Mateo released a demo of "Desde que te fuiste" (Since You Went Away), a latin dance song written by him and one of the tracks he is working on for his upcoming album on EMI Music Spain.It was released on iTunes on 9 December 2011.