Griezmann scored twice in Atleti's 3-0 win over Marseille in Lyon but has persistently been linked to a move away, with Barcelona reported to be among his biggest admirers.
The France international may have delivered the perfect parting gift to Atleti with his performance on Wednesday, but Simeone hopes there is more to come from the striker.
"Griezmann confirmed what I already know, which is that he is very good," said Simeone. "We hope he's happy and... with us."
The result earned Simeone his sixth trophy as Atleti coach and his second Europa League crown.
"I am happy," he continued. "We have been working very well year after year, we have been close to the titles, with two lost Champions League finals.
"Today we had the chance to win and we made a strong second half."
And the Argentine believes his absence from the touchline due to suspension had no impact on his players.
"Watching the game from the box was a sad experience, with a feeling of loneliness," he explained.
"We've been working together for six years and I have great trust in the players. Even if I'm at home or in the hotel, they perform the same."