He took his stage name from the character Roch Siffredi played by Alain Delon in the French gangster film Borsalino (1970). Known as the "Italian Stallion", Siffredi has starred in more than 1,300 pornographic films.

Siffredi met porn actor Gabriel Pontello in a French sex club in 1985 and was introduced to Producer Marc Dorcel and Director Michel Ricaud, who cast him in his first pornographic role, Attention fillettes... (Attention little girls...) in 1987, in which he performed anal sex. Siffredi then stepped away from porn and worked as a fashion model, but returned to the Business after two years with the help of porn Actress Teresa Orlowski. Siffredi went on to perform in both plot-based and gonzo-style pornography, with styles of sex ranging from ordinary to extreme. However, it was Siffredi's performances involving anal sex and analingus, as well as rough sex and his psychological intensity and athleticism, which earned him recognition and ultimately a cult following. Through collaboration with John Stagliano's Evil Angel studio and then his own Budapest-based Rocco Siffredi Produzioni as both a performer and Director, Siffredi became one of the most powerful and recognizable personalities in pornography. "Rocco has far more power in this industry than any actress", Stagliano commented in 2001. Siffredi has credited Stagliano with being his mentor through all 30 years of his career.

Siffredi had a three-year relationship with the Actress Louise Germaine. He is married to Rosa Caracciolo (born Rózsa Tassi), a Hungarian model whom he met in 1993 in Cannes and with whom he performed two years later in Tarzan X: Shame of Jane. Together they have two sons, Lorenzo and Leonardo. Upon his decision to return to on-screen pornographic performance in 2009, Siffredi recounted, "I spoke with my wife and she said it's my Problem only, it doesn't belong to her and the boys. And she said, 'You decided to stop; we never asked you. So if you want to go back, just go back". However, after a long period of intensive performing, with much time away from his home in Italy, Siffredi announced his retirement again in 2015 for the sake of his marriage. "Today I can see, my wife, she is the top priority", he said in a press statement. "She deserves to have what she wanted from day one, to be with only me without sharing with other girls". Caracciolo told the press, "I know him very well and I love him for who and what he is. Let's see what the new version of him will be like".

In 1997, Italian band Elio e Le Storie Tese dedicated a song and a video, "Rocco e Le Storie Tese", to Siffredi. Siffredi himself directed the video, also appearing in it. Siffredi also duetted with the band in the song "Un bacio piccolissimo" at the 63rd edition of the Sanremo Music Festival.

In 1999, he appeared in the controversial Catherine Breillat film Romance. His performance in this role was followed by a part specifically written for him by the same Director in her 2003 film Anatomie de L'enfer (Anatomy of Hell), in which he played a gay man who became sexually involved with a woman. Both films featured unsimulated sexual scenes involving Siffredi, although it is disputed whether he actually had intercourse with co-star Caroline Ducey in Romance (she said no, Siffredi said yes). In 2012, he made a cameo as himself in the successful French comedy Porn in the Hood.

In June 2004, Siffredi declared that he would retire from performing in porn for the sake of his children, and instead focus on direction and production. "My children are growing up", he said, "and I can no longer just say 'Dad is going to work to make money for the family'. They want to know more". Regarding Siffredi's long career, Axel Braun commented, "The Problem is that he's been trying for years to find an 'heir to the throne', but it's no easy task. He thought he found him in Nacho Vidal, but then Nacho went his own way". Siffredi, while continuing to direct, was largely absent as an on-screen performer for nearly five years. However, sexual frustration and disappointment as a Director with his male talent and the state of the porn industry overall led Siffredi to return as a performer in 2009. Despite renewed success, Siffredi announced his retirement once again in 2015, shortly after appearing on the Italian reality television show L'Isola dei Famosi (Island of the Famous) which saw him stranded naked and alone on a beach for one week. He was reported to have told a friend, "I never felt so naked as I did then. I was all alone and it gave me a lot of time to think about what is important. And I realised I don't want to lose my wife". He later told the press, "[M]ore than a year ago I started to get uncomfortable in the front of the camera... [S]omething inside of me has changed". However, he has continued performing sex in titles such as Rocco One on One and Rocco's Intimate Castings.