Youth, college and amateur

Caldwell spent a year with the New England Revolution academy, making six appearances in 2008-09 while rehabbing injuries. On February 9, 2009, it was announced that Caldwell committed to the University of Akron.^[2] In his freshman year, Caldwell made 19 appearances and went 2-for-2 in penalty kicks at the College Cup. In 2010, he made 24 appearances and scored five goals, including a game winner in the NCAA College Cup final against Louisville to capture the school's first ever national title in any sport.^[3] He also recorded an assist that year and was named Most Outstanding Offensive Player at the College Cup and Academic All-MAC. In his junior year, Caldwell finished first on the team in assists and second in points. He made 23 appearances and finished the year with six goals and 11 assists on his way to being named NSCAA All-America Third Team, CoSIDA Academic All-America Second Team, First Team All-MAC, Academic All-MAC and All-Ohio team. In his senior year, he led the team in points with 28. Appearing in 22 games and scoring nine goals and 10 assists on his way to being named NSCAA All-America First Team, NSCAA All-American Scholar Player of the Year, Mid-American Conference Player of the Year, Soccer America MVP First Team, Top Drawer Soccer's Team of the Season First Team, CoSIDA Academic All-America First Team, All-MAC First Team and Academic All-MAC.

During his college years, Caldwell also played in the USL Premier Development League for the Michigan Bucks, the Central Jersey Spartans and the Akron Summit Assault.^[4][5][6][7]

Professional

On December 21, 2012, Caldwell signed with MLS club New England Revolution the second Homegrown Player in club history.^[8] He made his professional debut for the club on March 16, 2013, in a 1-0 defeat on the road against the Philadelphia Union.^[9]

at the end of the 2021 MLS Season Caldwell's contract was not picked up after nine years at the Revolution.^[10] As of January 12, 2022, he is a free agent. His last appearance for the club was October 20 with an 89th-minute substitution in a 2–3 win on the road at DC United. His last start for the club was also a 2–3 win away to Chicago Fire on September 22.

On January 12, 2022, Caldwell signed as a free agent with Real Salt Lake on a two-year deal.^[11]

Club

As of match played May 7, 2023^[13]