He was the second-round pick of the 2008 draft who came in with a flash. He made a joke about Tony Romo's girlfriend the day he was drafted.
He quickly was told to keep quiet, and he didn't. It just fueled him to keep talking.
It got to the point where his YouTube, Ustream and Twitter entries made more of an impact than his play on the field.
Maybe it was his newfound money and fame that turned Bennett into an attention-seeking missile. At some point, the athletic ability, the reason he has the money and fame, needs to become the story.
It was only a preseason game, but Bennett's four catches for 40 yards with one touchdown Saturday made everyone realize he's making progress.
With his evening over, Bennett was sliding past a herd of reporters who were talking to owner Jerry Jones in the locker room when this comment came out.
"That guy right there," Jones said, "he played like he practiced this last week and played like he's worked in the offseason. That's Martellus Bennett. He looked like the player that he can be out there."
In another room about 20 minutes earlier, the quarterback whose job it will be to get the backup tight end the ball also offered praise.
"Martellus had a great game, but we got to look back on the tape and see the little things," Tony Romo said. "Aesthetically, just watching, it looked good. He did a good job getting in position. He made some good plays and we needed it."
Maybe it's time for everyone to notice Bennett's football talents instead of his skills to tell you who has the best mix tape.
This training camp was turning into the heartwarming tale of John Phillips and the Greek tragedy of Bennett.
Bennett missed the start of training camp with a sprained ankle suffered when he was working on his craft.
Phillips, the talented No. 3 tight end, came in healthy and wowed the coaches and scouts. He was catching everything in practice while Bennett was rehabbing. In the first preseason game, Phillips caught four passes for 60 yards.
Suddenly, Phillips became the off-Broadway play shut down after two days in the theater when he tore his ACL vs. the Bengals.
Bennett returned to practice and made almost every catch, looking smooth doing it. There were a few mistakes here and there, but the Cowboys were starting to see the potential emerge.
A new show was on the stage. The show the Cowboys were looking for.
"I think my team already does have confidence in me," Bennett said. "I think Romo does, the coaching staff does. I think they do believe in me this year. I will get more opportunities than I had in the past."
He still pops off now and then. When Wade Phillips said Bennett suffered a minor setback in camp with his injury, Bennett said on Twitter that he didn't.
The same praise showered on Phillips for being a tough prize fighter who battles through cuts and keeps fighting should now be aimed at Bennett.
As Bennett talked to a reporter late Saturday night, his left ankle was swollen the size of a softball. But it was a lot worse when he first injured it.
"It's been going down a lot. You can't tell right now," Bennett said. "It's been feeling better since I came back to practice. The trainers did a great job of getting me to come back to be ready."
You just start to wonder if Bennett is developing into a talented passing threat the Cowboys can depend on along with veteran starter Jason Witten.
On Saturday night, Bennett outjumped a smaller defender and used his body as a shield for a 19-yard touchdown. On the touchdown drive, Bennett made three receptions: one for a first down, another to set up a second-and-short, and the touchdown.
Maybe Bennett and the Cowboys are right about him reaching his potential.
"Once I get going, I think I'm pretty good," he said. "I got to keep working."