Omar Samuel Pasley was born in the parish of Clarendon, Jamaica. OMI established in Kingston, after being discovered by the dancehall impresario Clifton Dillon (known as Specialist) and signed to Oufah, an independent Jamaican label. His first recorded hit was "Standing On All Threes" released with a music video. OMI had composed a song titled "Cheerleader" in 2008. He eventually recorded it and performed and released in 2012. It was released in Jamaica along a low-budget, high-concept video shot in Oregon during OMI's first trip to the United States, becoming a modest hit in Jamaica and also popular in Hawaii and in Dubai. Never releasing an album, OMI had various local hits in Jamaica like "Take It Easy", "Fireworks" (accompanied by a music video) and "Color of My Lips", the latter featuring Busy Signal, a well-known Jamaican dancehall reggae artist.
In 2014, the track "Cheerleader" got a second life when Patrick Moxey, the president of Ultra Music, a dance label partly owned by Sony Music heard the song and liked it offering to remix the song and relaunch it as a dance track. In early 2014, Ultra Music commissioned two remixes for the song, one by Ricky Blaze and the other by Felix Jaehn, a 20-year-old German producer. Eventually Ultra Music opted for the airy tropical house version of "Cheerleader" as remixed by Jaehn.
The remix initially became a huge hit in Sweden, eventually certified 5 times platinum. Soon the song spread through other European charts, notably France, Italy and Germany. It topped the charts in several European countries and in Australia. In the United Kingdom, OMI made history on May 24, 2015, when "Cheerleader" topped the UK Singles Chart for a fourth week in a row, marking the longest consecutive period any Jamaican artist has held that position on the chart. In the United States, the song entered the Billboard Hot 100 in May 2015; It later made the top spot of the Hot 100 after 12 weeks in the chart.