Born in St. D'Acre, St. Ann, Jamaica, Romeo left home at the age of 14 and worked on a sugar plantation outside Clarendon, before winning a local talent competition when he was 18. This prompted a move to the capital, Kingston, in order to embark on a musical career.
In 1965, Romeo joined up with Kenneth Knight and Lloyd Shakespeare in The Emotions, whilst also working in sales for the Caltone label. The group were unsuccessful in auditions for other producers, but Ken Lack offered them an audition after overhearing Smith singing to himself while working. In 1966, the group had their first hit, with the Lack-produced "(Buy You) A Rainbow". The Emotions went on to release several hit singles, and by 1968, the singer, by that point known as Max Romeo began his solo career in 1968, but did not have any great successes on the charts. Romeo returned to The Emotions, now recording for Phil Pratt, and founded a new band, The Hippy Boys.
1968 saw the breakthrough in Romeo's career, when he wrote "Wet Dream", a song that became a massive hit in Jamaica. The track was banned by the BBC Radio in the UK due to its overtly sexual lyrics, although the singer claimed that it was about a leaking roof. Nevertheless, "Wet Dream" became a Top 10 hit in the UK, where it spent six months in the chart. Further records that came out in 1969 were "Belly Woman", "Wine Her Goosie" and "Mini-Skirt Vision", as well as Max Romeo's debut LP, A Dream. Romeo was banned from performing at several venues during a tour of the UK.
In 1970, Romeo returned to Jamaica setting up Romax, an unsuccessful record label and sound system, and released in 1971 his second album, Let the Power Fall. It included a number of politically charged songs, most advocating the democratic socialist People's National Party (PNP), which chose his song "Let the Power Fall" as their theme song for the 1972 Jamaican general election. After this, Romeo worked with producer Lee "Scratch" Perry on the album Revelation Time (1975), which featured the classic song "Three Blind Mice", an adaptation of the nursery rhyme with lyrics about a police raid on a party.
In 1976, Romeo released War Ina Babylon, an album perceived as his best work. The politically and religiously themed album included the popular single "Chase the Devil", which would become one of his most known songs. Shortly after this, the pair fell out, leaving Romeo to self-produce his follow-up album, Reconstruction, which, however, could not match the success of its predecessors when it was released in 1977.
In 1980, he appeared as a backing vocalist on "Dance" on The Rolling Stones album Emotional Rescue. In 1981, the favour was returned when Keith Richards of The Rolling Stones co-produced and played on Romeo's album Holding Out My Love to You, an unsuccessful attempt to break into the North American market.
The rest of his output during the decade went practically unnoticed, with Romeo finding work at a New York electronics store. John Holt encouraged him to return to Jamaica, and he lived at Holt's house in Meadowbrook for a year.
Romeo visited the UK again in 1992, recording albums Fari – Captain of My Ship (1992) and Our Rights (1995) with Jah Shaka. He joined up with UK rhythm section/production team Mafia & Fluxy in 1998 for the album Selassie I Forever. A compilation album, The Many Moods of Max Romeo, was released in the UK in 1999.
In 2014, he released the album Father and Sons, a collaboration with his sons Ronaldo and Romario (known as the duo Rominal). His daughter Azana Smith has also started a recording career under the name Xana Romeo.