The 19-year-old striker, who can play through the middle or on the wing, started the season at Yeovil but cut his loan spell short due to a lack of playing time.
The Tigers could hand Stewart his debut against Middlesbrough on Saturday and United reserve team boss Warren Joyce has backed the forward to make the most of his chance.
He told the Hull Daily Mail: 'He has got bags of pace and is a very hard-working lad. He has a good touch, he's quick and he can take players on. He can play anywhere in a front two or three or on his own. But he can also play out wide as a winger and come in off the flank.
'It's a good opportunity for him to go to Hull and he's looking forward to it. He knows it's a fantastic opportunity which has presented itself and he intends to make an impact, whether he starts or whether that's off the bench.'
Stewart has yet to feature for the United first team but was called up to the senior squad against Wolfsburg last season in the Champions League. His contract at Old Trafford expires in June.
England have capped Stewart at Under 17 and Under 19 level.
Source: Daily Mail
Source: Daily Mail