The guy following Rick in The Walking Dead is Daryl Dixon.

In The Walking Dead, Daryl Dixon is a main character who is known for his survival skills and expertise with a crossbow. He is portrayed by actor Norman Reedus. Daryl is introduced in the first season as a skilled hunter and tracker, and quickly becomes a valuable member of the group led by Rick Grimes. He is known for his tough and rugged exterior, but also shows moments of vulnerability and loyalty to his friends. Daryl’s character development throughout the series has made him a fan favorite, and he has become one of the most iconic characters in The Walking Dead.