In the absence of Paolo Di Canio and Steve Lomas at Middlesbrough, Glenn handed Joe the captain's armband last weekend and says: "Joe Cole led by example on Saturday and he is still a young man learning the game.
"He wants to learn and be a student of the game, where he understands not only his own position and role in the team, but the role of other players.
"That only comes through experience and a desire to learn all facets of the game, the duties and responsibilities, if you want, of everyone's position - which is what Joe has.
"When I told him he was captain his whole face lit up and he was so, so pleased.
"He told me in the summer that one day he would like to captain West Ham and when this first opportunity came along it was a pleasure telling him.
"I had a good feeling straight away that he would have an excellent game so I couldn't be more pleased for him - and I think everyone else responded.
"He has been at West Ham since he was 12 years old. He is one of our own, an Academy boy who has grown up in the West Ham traditions.
"Though, when he asked about the possibility of captaining West Ham back in the summer, I felt it wasn't the right time, which I told him at that time.
"But it has always been in the back of my mind, and I thought the occasion on Saturday was the right time to give him an opportunity - and I have to say he took it with both hands.
"And, having looked at the other players' performances, I have to say they responded to Joe being made captain in the right manner - which is terrific.
"He is the first to admit that, at 21, he can hardly know all aspects of the game yet and he is still learning his own role.
"But he has got an ability to lead by example. By him playing well, others see that, and get inspiration from his performance.
"He could not have given a better personal display on Saturday. By doing that he fulfilled the role of captain, and showed why I chose him.
"I think when he said it was his proudest moment in football, Joe is such a genuine young man you had better believe that."
Glenn was pleased with the performance of everyone at Middlesbrough, and says: "Michael Carrick gave a superb performance and there were lots of good ones out there. There wouldn't be anyone you could cast a critical eye over from Saturday.
"Ian Pearce, in his second game as a striker, showed a vast improvement. He did well against Southampton but he did a whole lot better against Middlesbrough.
"Everyone put in a performance and that is what we have to have for the rest of the season, starting on Saturday.
"You can't carry anyone at Old Trafford - you have to have 11 displays of top quality - which our players have the ability to put in."