He was born and raised in Miami, Florida until the age of six when his parents, Johannie Infante (née Santos), a court reporter, and father Eduardo Infante, computer analyst, divorced. He moved with his mother to Cooper City, Florida, where he lived until he graduated from Cooper City High School.
In 2011, he performed the role of Eric in the Off-Broadway production of 4 Martinis, which won the Best Ensemble award at the 2012 Fresh Fruits Festival.
In early 2014, he played the role of the Captain in Alan Roland's original play Flight of the Ibis, which co-starred opera singer Lauren Flanigan and David Margulies. He completed a sold-out, seven-date run of George Cameron Grant's original play Fortune, based on the life of Rose Fortune. He received further positive reviews in his portrayal of Uncle Nasir in the staged reading of Mohammed Saad Ali's play Old Men Are Full of S**t, also performed during the Midtown International Theatre Festival. According to Broadwayworld.com, "Kristoffer Infante juggles misery and fury with great agility."