Acquired: Selected in second round (No. 22 pick) of 2013 MLS SuperDraft.
2014: Started season with a foot injury. Sent on loan to Orlando City of USL PRO on July 25 for remainder of USL PRO season; Made NYRB first team debut on September 17, playing full 90 minutes in New York’s 1-0 CCL group play loss at Montreal. Made MLS regular-season debut on September 20 against Seattle as a second-half substitute. Replaced Thierry Henry as a second-half substitute on October 4 in a 1-0 win against Houston. Replaced Bradley Wright-Phillips on October 11 in a 3-1 against Toronto FC, playing two minutes as a second-half substitute… Playoffs: Did not appear… Champions League: Played full 90 in New York’s 1-0 CCL group play loss at Montreal on September 17. Played the full 90 minutes on September 24 in New York’s 0-0 draw at C.D. FAS in CCL group play.
2013: Did not make an appearance during his first MLS season… Playoffs: Did not appear … U.S. Open Cup: Did not appear … MLS Reserve League: Appeared in four reserve games, making three starts … Other: Appeared as a second-half substitute in 2-2 friendly tie vs. French club Olympique Lyonnais on July 16.
College: Christianson played four years for Georgetown, amassing 78 appearances (77 starts) and tallying 14 goals and 10 assists … Wrapped up his college career by making 26 starts as a senior in 2012, notching two goals and two assists, and captaining the Hoyas to the NCAA Division I final … That year, he was named third team all-America, first team All-Northeast region, and first team all-BIG EAST … Earned second team all-Northeast region and first team all-BIG EAST as a junior in 2011 and as a sophomore in 2010 … Named BIG EAST Midfielder of the Year in 2010 after notching five goals and seven assists in 20 game … That 2010 squad earned Georgetown's third all-time NCAA Tournament berth and first in 13 years.
Club: Prior to his prolific career at Georgetown, Christianson was a member of the Chicago Fire’s youth organization throughout high school.