He played college football for the Iowa Hawkeyes, earning unanimous All-American honors and winning the Doak Walker Award and the Jim Brown Trophy in 2008.

He attended Winslow Township High School in Atco, New Jersey, and played for the Winslow Eagles high school football team as the starting running back and linebacker for the Eagles during his junior and senior years.

In his junior year, Greene rushed for 1,267 yards and 18 touchdowns in 221 attempts earning first team all-conference, all-South Jersey, and all-state honors.

[5] On April 29, 2009, the New York Jets traded up 12 spots to select Greene in the third round (65th overall) of the 2009 NFL draft.

Greene made his regular season debut after a season-ending injury of Leon Washington during week 7 against the Oakland Raiders.

In the 2010 offseason, the Jets did not resign running back Thomas Jones and signed instead LaDainian Tomlinson to be their starter and Greene to be the back-up.

[19] Greene also rushed for 76 yard on 17 attempts and scored the game-closing touchdown against the Patriots in a playoff game.

On June 5, 2011, Jets offensive coordinator Brian Schottenheimer announced that Greene would be the starting running back in the 2011 season, with LaDainian Tomlinson taking a 3rd down role.

Greene got his first touchdown of the year in a Week 2 matchup between the Jacksonville Jaguars while adding 49 yards in 16 carries.

[22] On August 8 of a pre-season game Greene rushed for 32 yards on 5 carries and a 19-yard touchdown run in his Titans debut facing the Washington Redskins.

In the season opener against the Steelers, Greene rushed for 18 yards on 4 carries before injuring his knee that sidelined him for 5 weeks.

Greene played his former team, the New York Jets, later that year and rushed for 50 yards on 15 carries in a loss.