Howey was born in San Antonio, Texas, and began his acting career in the late 1990s with small roles in television shows and films. He gained wider recognition for his role as Van Montgomery on the CW television series Reba, which aired from 2001 to 2007.
In 2011, Howey began starring as Kevin Ball on Shameless, a role he continued to play until the show ended in 2021. He received critical acclaim for his performance on the show, and won a Screen Actors Guild Award for Outstanding Performance by an Ensemble in a Comedy Series in 2016.
In addition to his acting career, Howey is also a talented musician and has released several albums as part of the band L for Leisure. He is married to actress Sarah Shahi, and the couple have three children together.