After serving sixteen consecutive terms on the Boston City Council, he lost reelection in 2015 to Andrea Campbell.

While at Tufts, he helped found the Afro-American Society and the African American Cultural Center.

In the 2010s, a pet project of Yancey's was advocating for the creation of a "first class" high school in Mattapan.

[4][5] In 2011, Yancey was the only member of the Boston City Council to vote against an ordinance requiring fingerprints and criminal records to be provided by individuals applying for certain licenses.

[6] In a candidate survey for the mayoral race, Yancey announced positions on issues including keeping a cap on the number of charter schools in Boston, allowing for a citywide vote on a potential casino bid, and increasing the number of street workers in Boston to curb youth violence.