He played college football for the Virginia Tech Hokies prior to being selected by the Seahawks in the fifth round of the 2010 NFL draft.
[2] He attended Matthew Fontaine Maury High School where he played basketball and football as a quarterback and safety for the Commodores athletic teams.
Chancellor was named the team's most valuable player, and he was also placed on the All-Eastern District first-team as well as The Virginian-Pilot All-Tidewater second-team.
[9] Before his senior season in 2009, Hokies' defensive backs coach, Torrian Gray said that Chancellor could be "the greatest safety in Virginia Tech history.
[10] In his senior season, Chancellor recorded two interceptions, one fumble return, 68 total tackles, three tackles-for-loss, and four broken-up passes.
[19][20] Throughout training camp, he competed for a job at strong safety against Lawyer Milloy, Kevin Ellison, and Jordan Babineaux.
[21] Head coach Pete Carroll named Chancellor the third strong safety on the depth chart to start the regular season, behind veterans Milloy and Babineaux.
[23] On October 31, 2010, Chancellor recorded two solo tackles and sacked quarterback Jason Campbell in the Seahawks' 33–3 loss at the Oakland Raiders.
[24] He finished his rookie season with 23 combined tackles (17 solo), a pass deflection, a sack, and a forced fumble in 16 games and no starts.
[25] Chancellor entered training camp slated as the starting strong safety after the Seahawks opted to not re-sign Lawyer Milloy.
[26] He started the Seattle Seahawks' season-opener at the San Francisco 49ers and recorded a season-high ten solo tackles in their 33–17 loss.
[30] He finished his first season as a starter with 97 combined tackles (75 solo), a career-high 13 pass deflections, four interceptions, and a sack in 15 games and 15 starts.
[32] On January 25, 2012, it was announced that Chancellor was added to the 2012 Pro Bowl roster as a replacement for Dashon Goldson of the San Francisco 49ers.
[19][37] New defensive coordinator Dan Quinn retained Chancellor and Thomas as the starting safeties to begin the regular season.
[40] The Seattle Seahawks finished the season atop the NFC West with a 13–3 record and clinched a playoff berth and a first round bye.
On January 11, 2014, Chancellor started his first career playoff game and recorded 14 combined tackles (four solo) and two pass deflections during the Seahawks' 23–15 victory against the New Orleans Saints in the NFC Divisional Round.
[44] Chancellor began the season being selected as a team captain by his teammates, along with Russell Wilson, Jon Ryan, and Steven Hauschka.
He started the Seattle Seahawks' season-opener against the Green Bay Packers and recorded a season-high 11 combined tackles (eight solo) during a 36–16 victory.
On September 21, 2014, in a Super Bowl XLVIII rematch with the Denver Broncos, Chancellor recorded nine tackles, an interception, a forced fumble, and two passes defended in a 26–20 victory, winning the NFC Defensive Player of the Week Award.
[57] In the Wild Card Round of the postseason for the 2015 season, Chancellor would force a fourth quarter fumble of running back Adrian Peterson in a game against the Minnesota Vikings.
[70] Despite missing the final six games of the season due to that injury, Chancellor was named a Pro Bowl alternate at safety.
Chancellor had the honor of raising the 12th Man flag for the Seahawks 2018 home opener and later revealed that he had spinal stenosis and bone spurs in his neck.