His father Vincent Jr. was a top high school basketball player in Baltimore and later became a starter at Voorhees College in Denmark, South Carolina.

In his childhood, Delaney led his Pop Warner youth football team to the national title.

[1] At age seven, Delaney dribbled and shot balls on the sidelines at an Amateur Athletic Union (AAU) team practice.

McDonogh most notably defeated Mount Saint Joseph High School, the top-ranked team in the Maryland Interscholastic Athletic Association (MIAA).

[5] Before his sophomore year, Delaney transferred to Towson Catholic, where he continued to play MIAA basketball under head coach Josh Pratt.

He also played for AAU Team Melo and is friends with former New York Knicks star and Maryland native Carmelo Anthony.

He was ranked among the ACC leaders in scoring (6th, 18.1 ppg), assists (5th, 4.5 apg), free throw percentage (3rd, 86.9%) and minutes played (2nd, 36.5).

Delaney led the Hokies with 14 points and a career-high-tying 10 assists in the loss to Baylor in the second round of the NIT.

He won the Lou Carnesecca Award, given to the most valuable player of the Aeropostale Holiday Festival, after averaging 23.5 ppg, 6.5 rpg, 6.0 apg and 3.0 spg for the tournament.

In his junior year Delaney was a unanimous first-team All-ACC after recording a career-best 20.2 ppg for the season.

[11] On April 6, 2012, Delaney recorded his first career double-double after racking up 30 points and 10 assists in a 99–109 overtime loss to the Nanterre.

On July 2, 2014, Delaney signed a one-year deal with the Russian team PBC Lokomotiv Kuban.

He made his NBA debut in the Hawks' season opener on October 27, 2016, recording four points and five assists in 20 minutes off the bench in a 114–99 win over the Washington Wizards.

[22] On February 24, 2017, in a 108–90 loss to the Miami Heat, Delaney had five points and four assists and made only 2 of 10 shots from the field in his first career start as a fill-in for Dennis Schröder.

[25] On September 12, 2019, Delaney signed a one-year deal with an option for another season with Spanish EuroLeague powerhouse FC Barcelona.

[26] In his first game with FC Barcelona, Delaney racked up 8 points, 4 rebounds and 6 assists in a 92–86 win over the Obradoiro.