Walkes, 22, originally joined Atlanta United on January 26, 2017 on-loan from English Premier League side Tottenham Hotspur. Primarily deployed as a right back, Walkes made 20 appearances, 17 starts, and scored two goals in the MLS regular season. He returned to Tottenham following the 2017 MLS Cup Playoffs and was then loaned to Portsmouth for the remainder of the 2017-18 EFL League One season. He made 12 appearances and scored one goal on his team debut and added one assist.
Walkes transferred to Portsmouth permanently on July 18, 2018. During the 2018-19 season, he made 24 appearances while scoring one goal and helped lead the club to a fourth-place finish in the table, earning a berth in the League One playoffs. Portsmouth also won its first EFL Trophy after defeating Sunderland 5-4 in penalties in Wembley Stadium. Walkes made 10 appearances during the 2019-2020 season and scored one goal during EFL Trophy play.
He spent his entire youth career with Spurs and ultimately made his First Team debut against Gillingham on Sept. 21, 2016, subbing on for the final 10 minutes during a 5-0 win in the Third Round of EFL Cup. Walkes also appeared in two matches during the 2016 International Champions Cup (ICC) against Atletico Madrid and Juventus.