Despite starting only 22 matches under Mourinho this season, the England international believes the 'Special One' is the right man for the job.
"This club will be successful under Jose Mourinho," Rooney said.
"Having seen the way he works and how successful he has been, we will be successful.
"If we can win Europa League that will be three trophies in his first season."
United claimed the Community Shield at the start of the season and the League Cup in February when they defeated Southampton 3-2.