Mazo was born in Gomel, Belarusian SSR into a Jewish family. He has been dancing since he was 5 years old. At age 12, he immigrated from the Soviet Union to San Antonio, Texas, and later to San Francisco, where his former engineer mother, Natasha, began a dance school. Mazo began studying dancing there at 16 in order to improve his socialization skills with girls, and to ease his back problems.
He studied computer science, and then cognitive science at the University of California, Berkeley, in the hopes of one day becoming a dance teacher. After DWTS, Mazo went to Stanford University to get his MBA. He currently runs a production company specializing in live stage entertainment and television reality formats.
Mazo worked as the CEO of the Genesis Dance Sport studio in San Francisco. Expanding the studio into Los Angeles has been one of his goals. He has one brother, Genya, who's also a ballroom dancer and has performed on the Dancing with the Stars tour. Alec Mazo is married to his long-time dancing partner dancer Edyta Śliwińska, a native of Poland. The couple welcomed a son, Michael Alexander Mazo, on January 4, 2014.
Mazo appeared in the 1998 movie Dance With Me. Mazo turned professional shortly before producers of Dancing with the Stars began their search for dancers to star on the show.
Mazo won the first season of Dancing with the Stars with his partner, Kelly Monaco.
Mazo returned to the ballroom on March 19 for Season 4, this time partnered with former supermodel Paulina Porizkova, but were the first couple eliminated. Despite being eliminated first, Paulina along with Shandi Finnessey (Who was eliminated the very next week) Both hold a higher average than a few celebrities who lasted longer than them.
Mazo appeared on the fifth season of Dancing with the Stars. Mazo and his partner, supermodel Josie Maran, were eliminated on September 26, 2007, after the first week of competition, making it the second time in a row he was eliminated first.
Mazo competed for the title with partner, Grammy Award-winning singer, Toni Braxton in Season 7 of Dancing with the Stars. After six dances, Braxton and Mazo became the fifth couple to be eliminated from the season.
In Season 9, Mazo was paired with Olympic swimmer, Natalie Coughlin. They were the fifth couple to be eliminated despite relatively good scores and received a standing ovation from the crowd and judges.
With celebrity partner Kelly Monaco: 23.0
With celebrity partner Paulina Porizkova: 20.0
With celebrity partner Josie Maran: 16.0
With celebrity partner Toni Braxton: 22.6
With celebrity partner Natalie Coughlin: 22.5