Youth DeLeon played three years for
Thunderbird High School in
Phoenix, Arizona from 2004 to 2007. DeLeon started his collegiate career at
University of Nevada, Las Vegas in 2008, and led freshmen in appearances with 18, starting in 12, and earned 3 assists in his first year. DeLeon scored two goals and two assists in 12 appearances his sophomore year. In the summer of 2010, DeLeon took part in and scored in the
U.S. Open Cup with Phoenix-based
NPSL team
Arizona Sahuaros. DeLeon transferred to the
University of Louisville for the 2010 season. DeLeon had a successful first season with the Cardinals, starting all 24 games and scoring 8 goals and 3 assists, and was named to the All-Big East first team. The Cardinals won the 2010 Big East Soccer Tournament and advanced to the final of the
2010 College Cup, where they fell 1–0 to the
Akron Zips. In DeLeon's senior season at Louisville, he again started every game, scoring 6 goals and 6 assists, and was again named to the All-Big East first team. DeLeon's two goals in the Cardinals' first two games helped them to the quarterfinals of the
2011 College Cup and saw him named to the Cup's All-Tournament team. DeLeon was invited to the 2012
MLS Combine based on his strong collegiate performances.
Professional DeLeon signed with
Major League Soccer on December 29, 2011, and was chosen with the 7th overall pick of the
2012 MLS SuperDraft by
D.C. United. He made his first appearance for United on March 18, 2012, coming on as a substitute in the second half against the
LA Galaxy. He scored D.C.'s only goal in a 3–1 loss, curling a right-footed shot just inside the back post, earning DeLeon a nomination for Goal of the Week. On November 8, DeLeon scored the winning goal in the 88th minute to knock the
New York Red Bulls out of the playoffs and to take
D.C. United to the Eastern Conference finals, where United were defeated by the
Houston Dynamo. DeLeon would feature in 28 games on the season, starting 25, running up a total of six goals and four assists. In the post-season, DeLeon was voted runner-up for the 2012 MLS Rookie of the Year award, losing out to fellow
University of Louisville alum
Austin Berry of the
Chicago Fire. On November 1, 2018, DeLeon scored a volley in the 116th minute of an MLS Playoff game against
Columbus Crew. DeLeon eventually missed the decisive penalty as the Crew won 3–2 on PK's. Following the 2018 season, D.C. declined the 2019 contract option on DeLeon. In December 2018, he was selected by
Toronto FC in the
2018 MLS Re-Entry Draft. DeLeon scored his first goal for
Toronto FC in the 2019 season opener on March 2, 2019, against
Philadelphia Union. He scored a goal against his former club,
D.C. United on June 29, 2019. He scored against D.C. United again in the
2019 MLS Cup Playoffs on October 19, 2019. The game ended in a 5–1 win for Deleon's side. On October 30, 2019, Deleon scored the winning goal against
Atlanta United FC in a 2–1 win. He departed Toronto FC after the 2021 season. ==International career==