Sapong played college soccer at James Madison University, where he ended his career with 37 goals and 21 assists in four seasons from 2007–2010. He was awarded First Team All-Conference and team Offensive MVP honors all four years, a first in program history, and was the CAA Player of the Year as a senior co-captain in 2010. Sapong was a two-time NSCAA First Team All-South Atlantic Region selection. As a freshman, he was named the CAA and VaSID Rookie of the Year and chosen to the Third Team All-South Atlantic Region. Sapong made eight appearances for Fredericksburg Gunners in the USL Premier Development League in 2009, and made eleven appearances and scored four goals for Reading United during their 2010 PDL season.
On January 14, 2011, Sapong was drafted #10 overall in the 2011 MLS SuperDraft by Sporting Kansas City. He signed with the club on March 1, 2011. He made his professional debut on March 19, in Kansas City's opening game of the 2011 MLS season against Chivas USA; he scored his first professional goal after just two minutes of the game, helping his team to a 3–2 victory. Sapong was awarded the MLS Rookie of the Year Award for 2011, edging out Perry Kitchen and Michael Farfan, who finished second and third, respectively.
Sapong was loaned to USL Pro's Orlando City in July 2013. On July 18, only a week after being loaned to Orlando, Sapong was recalled by Sporting Kansas City. In total, Sapong scored one goal in three matches while tallying one assist.
On December 8, 2014, Sapong was traded by Kansas City to Philadelphia Union in exchange for a first-round pick in the 2015 MLS SuperDraft. After several seasons of being deployed on the wing with Kansas City, Sapong was positioned as the Union's lone center forward, taking advantage of his strength and hold-up play. He led the Union in goals during the 2015 season and would build on those totals in subsequent seasons. He scored his first career hat-trick in Philadelphia's 3-0 victory over the New York Red Bulls at Talen Energy Stadium on May 6, 2017. On October 22, 2017, Sapong broke the Union's single-season scoring record, previously held by Sebastian Le Toux. At home against Orlando City, on the final day of the season, Sapong scored his fifteenth and sixteenth goals for the record.
Chicago Fire
On February 23, 2019, Sapong was traded by Philadelphia to Chicago Fire in exchange for up to $450,000 in Allocation Money. The specifics of the Allocation Money are as follows: $200,000 in 2019 General Allocation Money, $100,000 in 2020 Targeted Allocation Money, and an additional $100,000 in 2019 General Allocation Money to be conveyed to Philadelphia should the Chicago Fire acquire said funds this year. If the Fire do not acquire an additional $100,000 in 2019 General Allocation Money to convey to Philadelphia this season, then that money conveys as GAM in 2020, and the Union also receive $50,000 in 2020 Targeted Allocation Money from Chicago should Sapong hit certain performance incentives in 2019.
On February 23, 2017, Sapong helped launch the Sacred Seeds foundation, which promotes and enhances the growth of underserved communities through sustenance and self-sustainability. He was inspired by his own experiences recovering from injuries during his soccer career and being reluctant to rely on painkillers rather than more nutritional methods.
Legal issues
On May 1, 2015, Sapong was arrested for DUI and reckless driving. He was found not guilty of the DUI charge but still faced the reckless driving charge and was still forced to have attended an MLS league-mandated stint at a treatment facility in Malibu, California. Sapong has credited the experience with having "changed life."
