"He has earned the right to be our quarterback," Romo said. "As hard as that is for me to say, he's earned that right. He has guided our team to an 8-1 record and that's hard to do.
"If you think for a second I don't want to be out there, then you probably never felt the pure ecstasy of competing and winning."
Romo made the declaration while reading from a prepared statement at the Cowboys' facility. He didn't take questions from reporters and said it was in "the best interests of my team" not to do so.
Romo appeared emotional at times during his statement and reflected on different aspects of his National Football League career.
The 36-year-old Romo is now recovered from an August back injury that opened the door for Prescott to become the starter. Prescott has taken advantage of the situation and led Dallas to the best record in the NFL through 10 weeks of the season.
Romo said no one player is bigger than the team which is a refreshing change in a US sports era that is dominated by millionaire athletes motivated by self-interest.
While disappointed at not being able to play on what he called the best Cowboys team during his 14 seasons, he gave his full support to Prescott.
"I think you all know something magical is happening to our team," Romo said.
"I'm not going to allow this situation to negatively affect Dak or this football team by becoming a constant distraction.
"I think Dak knows that I have his back and I think I know that he has mine.
"Ultimately, it's about the team."