He is perhaps best known for his recurring roles on two television series: Fin Tutuola's son Ken Randall on Law & Order: Special Victims Unit, and Omar Little's boyfriend Dante on The Wire.
[1] His credits also include the television series As the World Turns and One Tree Hill, and the film The Poker Game.
He developed an interest in acting and attended a summer program at the Oxford School of Drama before enrolling at New York University.
When accepting his first recurring role, Waddell was apprehensive because he thought that appearances in The Wire would lead to him being typecast.
Referring to Waddell, Victoria Cartagena has stated that the two of them were cast in The Bedford Diaries because he helped her practice lines while waiting for an audition.