Portgas D. Ace is the adopted older brother of Monkey D. Luffy. He served as the 2nd division commander of the Whitebeard Pirates and one time captain of the Space Pirates. He was eventually caught by the World Government and was sentenced to death. This resulted to the Battle of Marineford. Ace was set free, but he sacrificed his own life to protect his little brother.
In the 4Kids dub, he is voiced by Jesse Hooker. When FUNimation got the license, he is voiced by Travis Willingham. In a lesser known Englsih dub by Onex released in Singapore, he is voiced Dwayne Tan.
Travis Willingham: Now this a better portrayal for Ace. Both serious and humorously, Travis delivered his lines very well.
Jesse Hooker: While I find the 4Kids dub abysmal, Jesse's portrayal as Ace was only one of the few decent ones. Along with Zoro and Smoker. Still, he's not perfect, but better than most voices in the 4Kids version.
Dwayne Tan: For once in my life, I've never seen the Odex version back then. Looking at Dwayne's performance as Ace - he's pretty bland.