Steele has been the subject of criticism from small sections of Middlesbrough supporters, but Mowbray has hailed the form of the 22-year-old.
Mowbray told the Evening Gazette: "Jason's form has been magnificent all season. In my time here I've heard the murmurings but you've got to give young goalkeepers opportunities to play.
"I think he's doing exceptionally well. He's a big, big talent and his personality's great for the job and he's going to be very important for us."
Steele was named man of the match as Middlesbrough beat Watford 2-1 last weekend.