Bennett was named in Stuart Pearce's party for Tuesday's friendly with Italy in Empoli earlier this week.
The 20-year-old came close to leaving Middlesbrough earlier in the season, when he was cast into the wilderness by former manager Gordon Strachan.
Mowbray's arrival led to a change in his fortunes, and the Northallerton-based fullback has started Boro's last 14 Championship matches.
His performances have consistently caught the eye, and Mowbray feels his elevation to Under-21 level is thoroughly deserved.
I'm delighted for Joe,
said the Boro boss. Although I'm also pleased they (the Under-21 selectors) didn't come and watch the first half of Tuesday's game because he was probably Scunthorpe's best player before half-time!
Seriously though, Joe's a wonderful talent. I've been impressed from the day I first walked in the building and saw this little skinny kid dribbling around everyone.
His passing is excellent and I like the way he plays with his head up..
There are things we still have to work on with him, and he knows that. We have to nurture him, but he has a great attitude and hopefully he will go on to be a big player for us.
Bennett is merely the latest in a long line of Academy products to have established themselves in the Boro first team.
Of the 11 players that finished Tuesday's 2-0 win over Scunthorpe, seven had progressed through Boro's much-vaunted Academy.
The likes of Adam Johnson, Stewart Downing and Lee Cattermole have already moved on, and Mowbray feels privileged to be working with acclaimed Academy director Dave Parnaby.
Whenever you go into a new club, there are always things you want to change,
he said. Here, there were some things I wanted to change radically. But in terms of the Academy, I could very quickly see that I didn't need to change a thing.
I know Dave's footballing philosophy and he likes everyone in the Academy to play football the way I like it to be played. So when people like Joe and Cameron (Park) come through, I don't have to worry about their grasp of the basics.
Middlesbrough travel to Leeds United or Aston Villa in the quarter-finals of the FA Youth Cup.
Source: Northern Echo
Source: Northern Echo