Chapman attended Oak Grove High School in San Jose, California, where he played football and basketball.
Chapman was not offered any scholarships after graduating from high school, so he decided to stay close to home and play for the City College of San Francisco Rams.
With the help of future Wildcats teammate Nigel Malone, he led his team to a 12–1 record in 2010, as well as the school's 11th NorCal Championship.
[2] His playing time increased as a senior in 2012, and he recorded career highs in tackles (57), interceptions (6) and passes defended (10).
On November 3, he tied the Big 12 Conference single-game record by making three interceptions – including one he returned 29 yards for a touchdown – in a 44–30 win over Oklahoma State.
[4] After going unselected in the 2013 NFL draft, Chapman was signed by the Indianapolis Colts as an undrafted free agent on May 12, 2013, after participating in rookie camp as a tryout player.
[5] Coincidentally, the Colts released Nigel Malone (who played with Chapman at CC of San Francisco and Kansas State) in order to make space for the rookie cornerback.