Born in Atlanta, Georgia, Cronin attended Mount Tabor High School in Winston-Salem, North Carolina where he moved with his family in 1999.

[3] Cronin ultimately finished as second runner-up for the trophy,[4] but won the 2008 Lowe's Senior CLASS Award for Men's Soccer.

[8] Cronin made his professional debut on 21 March 2009, in Toronto's first game of the 2009 MLS season against Kansas City Wizards.

[11] He was selected as a member of the 2015 MLS All-Star Game, coming on at the start of the 2nd half, before being subbed off for Jozy Altidore in the 77th minute.

On July 11 Cronin made his debut with the United States against Haiti, lending a hand in the opening goal in the 2–2 draw.