After playing college football for the University of Tennessee and McNeese State, he was signed by the New York Giants as an undrafted free agent in 2012.
Jackson initially attended Carencro High School in Lafayette, Louisiana, until 2007 where his father, was the head coach of the football team.
After his father returned to McNeese State, Jackson attended Alfred M. Barbe High School in Lake Charles, Louisiana, where he made 92 tackles and intercepted 5 passes as a senior.
He was also named Class 5A All-State a second time and received All-American honors by USA Today and SuperPrep,.
"[6] Until midseason, Jackson had started all but two of the Volunteers' games and had emerged as one of the better freshman players in the Southeastern Conference (SEC).
On November 12, 2009, Jackson and fellow freshmen teammates Mike Edwards and Nu'Keese Richardson were arrested after an armed robbery attempt at a Pilot station on Cumberland Avenue in Knoxville, Tennessee.
[7] Less than two weeks later, charges against Jackson were dropped because a police investigation found that he had no prior knowledge of the alleged attempted robbery.
[12] On August 24, 2011, the University of Tennessee announced that Janzen Jackson was released from the football team for unspecified reasons.