Later that year, he was signed to the practice roster of the Toronto Argonauts of the Canadian Football League (CFL).

He earned All-Greater Spokane League first-team and All-State Class 4A honorable mention as a junior, amassing 2,011 yards with 17 rushing touchdowns in nine contests.

He opened the season with four 200-yard rushing performances and by midseason, he had shattered the previous school record of 1,299 yards on the ground by Tim Lappano in 1974.

He totaled 2,518 yards with 33 touchdowns on 281 carries (8.96 ypc), becoming the only player in district annals to produce a pair of "top ten" rushing seasons on the annual record chart.

[11] Regarded as a four-star recruit by Rivals.com, Sankey initially gave a "soft verbal" commitment to Washington State University as a junior in December 2009,[1] then changed his mind as a senior - “on letter of intent day” & accepted a scholarship from head coach Steve Sarkisian to play football at the University of Washington.

He also added six receptions and in the Alamo Bowl's wild 67–56 loss to Baylor, and also handled kickoff return duties.

With Chris Polk having left for the National Football League, the Huskies opened the 2012 campaign with Sankey in a reserve role.

When junior halfback Jesse Callier was injured in Washington's first game against San Diego State, Sankey stepped into the starting lineup the next week and never relinquished his role with the first unit.

He also served as a safety valve for quarterback Keith Price, catching 16 of the 22 passes targeted to him, good for 249 yards.

He led the team in scoring with 96 points and registered 1,688 all-purpose yards, the seventh-best figure by a Husky in a season.

[15] After being named one of the team's offensive captains, Sankey rewarded his teammates for that honor when he exploded for 161 yards and two touchdowns on 25 carries in the 2013 season opener against Boise State.

With his mother, aunts and uncles in the stands at Chicago's Soldier Field, Sankey exploded for a career-best 208 yards and a touchdown on a career-high 35 carries against Illinois.

He would establish school career and season records when he again reached the 200-yard rushing level in the 2013 Apple Cup against Washington State.

During his junior season, Sankey also proved to be a highly capable blocker, registering seventy-six knockdowns and 10 touchdown-resulting blocks.

[33] On September 5, 2018, Sankey signed with San Diego Fleet of the Alliance of American Football (AAF) for the 2019 season.

[34] He suffered an injury before the season began and was placed on the roster exempt list,[35] a designation that later became injured reserve.