The Malian put Reading ahead early on and then headed home a late winner after Craig Gardner had levelled from the spot.
And the Reading boss was delighted with Kebe, telling Sky Sports: "He has been brilliant for me in the three years I have had this job.
"He really is a great guy and loves playing for Reading - he scores goals and makes goals, it was fantastic for him today."
McDermott was happy with how his side responded to Sunderland getting back on level terms.
"You get setbacks in football and you just have to pick yourselves up and go again and I think the players did that, with the ball we were very good at times and we could just not get the second goal when we were winning but they have top quality players and that is a big win for us," he said.
"Once again we have had to come back, we went into the lead early on in the game but obviously Sunderland got a penalty and got back in the game.
"We then put a couple of strikers on and tried to win the game, and fortunately Ian Harte puts a brilliant ball into the box for Kebe and we are delighted with the win today."
Adam Le Fondre again had to make do with a place on the bench despite his goalscoring exploits of recent weeks- but McDermott insists he is taking it well.
"When you have a player like Adam Le Fondre it is tough for me to pick teams," he said.
"I try to explain to the players I am doing the best I can to get a result - and I spoke to him but he is sharp and knows. He wants to play every game, and he came on today and made a difference but the most important thing for Adam Le Fondre is that Reading win and that tells you something about the man."
McDermott was also very happy with recent signing Hope Akpan - who impressed on his full Premier League debut.
"You saw him today, he is strong, quick and can run with the ball - he is a team man," he said.
"And Nick Blackman came on and won the free-kick from how we got the winner so I was delighted for those guys."