Sanz was born in Madrid, Spain, on December 18, 1968, the youngest son of María Pizarro and Jesús Sánchez. He grew up in the neighborhood of Moratalaz in eastern Madrid. Sanz recalled that “Back then, kids grew up on the street…I was a bit like the group troubadour; the one who played the guitar and sang. That kept me out of a lot of trouble.” Sanz’s father, a door-to-door book salesman, played guitar professionally, which inspired seven-year-old Sanz to learn to play the instrument. He pursued the instrument with an intensity that eventually frustrated his mother, who broke his guitar one morning after his playing kept the family from sleeping.

As a teenager, Sanz performed in various venues in his hometown. He became acquainted with Miguel Ángel Arenas, a music industry executive who had signed several popular Spanish groups such as Mecano. Arenas helped Sanz find work, eventually leading to a record deal with the Spanish label Hispavox. In 1989 Sanz released his debut album, Los Chulos Son Pa’ Cuidarlos under the name of Alejandro Magno (Spanish for “Alexander the Great”). The record, which fused techno and flamenco, was met with critical and commercial indifference, and today Sanz views the record to be “insignificant”. However, the album is now considered to be a collector’s item. In an attempt to promote Los Chulos Son Pa’ Cuidarlos, he performed at strip clubs, playing short sets between acts. This proved to be unsuccessful and Sanz took a break from music, choosing to study business administration. He also took a job at a recording studio in which he wrote material for other artists. He persuaded Arenas to send demos of his songs to record companies, which led to being signed by Warner Music Latina. At this time, he began performing under his current name.

Sanz’s rise to fame began in 1991, when he released his first album from Warner, Viviendo Deprisa. The record and the songs “Pisando Fuerte” and “Se le Apagó la Luz” helped him gain a dedicated fan base in Spain. In 1993, he released Si Tú Me Miras shortly followed by a live album, titled Básico. That same year, he recorded a song entitled “Mi Primera Canción” with flamenco pioneer Paco de Lucía, whom Sanz idolized as a child. He released his third studio album since changing his stage name, 3, in 1995. In addition to Spanish, 3 was also released in Italian and Portuguese. “La Fuerza del Corazón”, the first single released from 3, was his first song to chart internationally. All three albums proved to be successful, reaching multi-platinum status in Spain.

Sanz spent two years in Milan, Italy to work on a follow-up for 3. For the album, he wished to create a “true fusion” of many different sounds, and began studying the saxophone and piano in addition to guitar. In 1997, Sanz released his fifth studio album, Más, a record containing ballads strongly influenced by flamenco, pop, and tropical rhythms. Driven by the singles “Corazón Partío”, “Y, ¿Si Fuera Ella?”, “Amiga Mía”, “Aquello Que Me Diste”, and “Siempre Es de Noche”, Más sold more than two million copies in Spain and was certified 22× Platinum in the country, making it the best-selling album in Spanish history. The album remained on the Billboard Latin Albums chart for 74 weeks, and one year after the record’s release, Sanz was granted an Ondas Award for Best Song for “Corazón Partío”. According to David Cazares of the South Florida Sun-Sentinel, the album “made Sanz an international star on the strength of the pop-salsa hit ‘Corazón Partío’, a song on the lips of fans from Spain to Cuba and the United States.” Following the success of the album, Sanz began touring in United States for the first time.

Sanz married Mexican fashion model and actress Jaydy Michel in Bali on December 30, 1999, but this marriage was never legally recognized in either of their home countries. Sanz felt that having a legally recognized marriage was unnecessary: “My wife is my wife and I am her husband. For me, that has enough validity…I am married with the heart.” Their daughter, Manuela Sánchez Michel, was born on July 28, 2001. The couple separated in 2005. Sanz later had a son named Alexander with Valeria Rivera, a Puerto Rican fashion designer.

His fifth album, El Alma al Aire, released September 26, 2000, featured Sanz exploring a wider array of musical genres, including jazz, R&B, soul and tango. In Spain, the album sold more than one million copies in the first week, breaking the record of one million copies sold in four months, also set by Sanz with his previous album, Más. At the 2001 Latin Grammy Awards, Sanz walked away with four awards: Best Pop Male Vocal Album and Album of the Year for El Alma al Aire, and Record of the Year and Song of the Year for the title track from the album. Later that year, El Alma al Aire was released in a special edition including Sanz’s duets with Irish band The Corrs. In October 2001, Sanz collaborated with Michael Jackson and various other artists on the Spanish version of the charity single “What More Can I Give”, which benefited the victims of the September 11 attacks.

In 2002, Sanz recorded MTV Unplugged at the Gusman Center for the Performing Arts in Miami, Florida. He was the first Spanish artist to record and release an MTV Unplugged album. For Sanz, the recording of the album “changed the way I do my music. It was a rediscovery of how to perform, and also how to record, music with live musicians. That was the spirit of the music in its pure form, though [it is ironic] that the more people who are playing, the more simple it is.” With the MTV Unplugged, he garnered three Latin Grammy Awards (Album of the Year, Recording of the Year and Song of the Year for “Y Sólo Se Me Ocurre Amarte”). At the 2002 Grammy Awards, Sanz performed “Quisiera Ser” as a duet with Destiny’s Child, with both Spanish lyrics and English lyric adaptation “I’d Like To Be Your Laughter”.

On September 2, 2003, Sanz released his sixth studio album, No Es lo Mismo. On this record, Sanz took a more political approach than he had on previous releases. The song “Sandy a Orilla do Mundo” discusses oil spills on the Spanish coast, while “Labana” tells the story of people fleeing from Cuba on makeshift rafts. The album won four awards at the 2004 Latin Grammy Awards, including Album of the Year and Record of the Year. Sanz was unable to attend the event and his awards were accepted by presenters and colleagues. Also in 2004, he became the first Spanish musician to give a lecture at Harvard University, speaking about Hispanic culture at the David Rockefeller Center for Latin American Studies.

In 2005, Sanz collaborated with Shakira on her song “La Tortura”. Co-written by Sanz, the song became an international hit, breaking the record for the most weeks at the number one spot on the Hot Latin Songs chart. The song exposed Sanz to a more diverse audience, and helped build anticipation for his next release. The first single from the album El Tren de los Momentos, “A la Primera Persona”, became his first song to enter the Billboard Hot 100, peaking at number 100 on the chart. The record was also noted for its guest appearances, which featured Shakira, Juanes, Alex González of Maná, and Residente of Calle 13.

In the spring of 2007, Sanz suffered a mental breakdown and took two months off in the middle of a world tour at the request of his doctor. The breakdown was caused by several events in his personal life, including the death of his father in 2005, his separation with Mexican model and actress Jaydy Mitchel, and his announcement that he had a three-year-old son outside of his marriage with Mitchel. He commented on the situation, saying “You have to put things in perspective. It was stress, something that had never affected me, but this time, yes, it did. So I had to pay. A doctor told me to stop for a couple of months to recuperate completely.” Sanz spent time in therapy, a time which “helped [him] a lot” and gave him “more power” to perform.

In a press conference in late 2007, he criticized Venezuelan president Hugo Chávez, calling him “undemocratic” in the wake of a petition made by Venezuelan citizens to prevent Chávez from running for re-election. Sanz further stated “If they gave me 3 million signatures to stop singing, I would stop singing immediately.” Supporters of Chávez subsequently gathered 230,000 signatures in response to Sanz’ comments.

To promote his new record, Paraíso Express, Sanz started a campaign in which fans could create a video about their definition of paradise and upload it to his YouTube channel. Artists such as Shakira, Laura Pausini and Paulina Rubio also participated. On November 10, 2009, Sanz released Paraíso Express. This record was described as a return to form for Sanz, focusing more on melody as opposed to the experimentation he pursued on his previous two albums. He commented that “On this album, I first composed the melody and then the lyrics. It is more of a rock album than my past releases, with more elegant and positive lyrics and a happier and more rhythmic spirit.” The bilingual single “Looking for Paradise” featuring Alicia Keys reached number one on the Billboard Hot Latin Songs chart. At the 2010 Latin Grammy Awards, the album was nominated Album of the Year and Best Male Pop Vocal Album, while the single “Desde Cuándo” received both Record and Song of the Year nominations.

On February 15, 2011, Sanz announced that he would be signing with Universal Music Group after twenty years with Warner. In the same year, Sanz received the Latin Heritage Award by the American Society of Composers, Authors and Publishers (ASCAP) in recognition of his contributions to Latin music. On September 2, 2012, the singer unveiled the official artwork of his upcoming ninth studio album, La Música No Se Toca on his official site. Sanz released La Música No Se Toca, featuring the single “No Me Compares” and based on the opening theme song in the telenovela Amores Verdaderos, on September 25, 2012. On August 21, 2012, Sanz released his new single “Irrepetível (Me Sumerjo)”, a duet with Brazilian singer-songwriter Ana Carolina. The song is a Portuguese-Spanish song and it’s only available in Brazil’s iTunes. On September 17, he released the album’s second single, “Se Vende”. In 2013, Sanz was recognized as the Pop Male Artist of the Year and was the recipient of the Excellence Award at the 26th Lo Nuestro Awards for his achievements in the music industry.

Sanz married his former assistant, Raquel Perera, on May 23, 2012 in a private ceremony held in Sabadell, Barcelona. They have two children: a son, Dylan, born in 2011 in New York, and a daughter, Alma, born in 2014 in Madrid. The couple separated in July 2019.

On November 6, 2013 Sanz received an honorary doctor of music degree from Berklee College of Music. “It is a great honor for me to receive this doctorate degree from one of the most prestigious music schools in the world,” Sanz said of the Berklee recognition. “I will continue to work every day of my life to deserve this honor.” Sanz released his eleventh studio album, Sirope, featuring the single “A Que No Me Dejas”, a collaboration with Alejandro Fernandez and used as the opening theme song in the telenovela A Que No Me Dejas, on May 4, 2015. The album took a year and one month to record, and features an “eclectic sound” in Sanz’s words, containing elements of flamenco, R&B, and folk music. He worked with producer Sebastian Krys, who helped him “enrich what was there but [not lose] the essence” of the songs. Alejandro Sanz was honored as the Latin Recording Academy’s Person of the Year on November 16, 2017.

He released his album #ElDisco in April 2019. The album was recorded in Miami and features collaborations Camila Cabello, Nicky Jam, Residente, and Catalan singer-songwriter Judit Neddermann. In May 2020, Sanz announced the new dates for his La Gira tour, which was originally slated to begin in June 2020 but was rescheduled to June 2021 due to the COVID-19 pandemic. The tour will begin on June 12, 2021 in Valencia.