After watching a montage of his films at the ceremony hosted by Russell Brand, Johnny joked: "This is the get of the business award. Based on watching all of those clips there is clearly something wrong with me."
The MTV Generation Award is the MTV Movie Awards' highest honor, with past recipients including Reese Witherspoon, Sandra Bullock, Ben Stiller, Adam Sandler, Mike Myers, Tom Cruise and Jim Carrey.
Johnny then surprised the star studded audience by strapping on his guitar and joining The Black Keys for a no-holds-barred rendition of the rock duo's 'Gold On the Ceiling'.
'The Hunger Games' was the big winner of the night, picking up gongs in four categories, Best Female and Best Male for Jennifer Lawrence and Joshua Hutcherson along with Best Fight and Best On-Screen Transormation.
'Bridesmaids' took home two awards, with Melissa McCarthy winning for Best Comedia Performance while the entire cast shared the Gut Wrenching Performance award for the scenes where food poisoning turned a wedding dress fitting in to a disaster.
Emma Watson picked up the Best Cast awards on behalf of her 'Harry Potter' co-stars while 'Harry Potter and the Deathly Hallows' was voted the winner in the Best Hero category.
Kristen Stewart and Robert Pattinson took home her fourth-straight win in the Best Kiss category for 'The Twilight Saga: Breaking Dawn - Part 1' while Jennifer Aniston was a surprise winner for Dirtbag of the Year for her role in 'Horrible Bosses'.
The audience was also treated to a sneak peak of 'The Dark Knight Rises,' introduced by director, writer and producer Christopher Nolan, along with cast members Christian Bale, Joseph Gordon-Levitt and Gary Oldman.
Winners of the 2012 MTV Movie Awards
MOVIE OF THE YEAR
'The Twilight Saga: Breaking Dawn - Part 1'
BEST FEMALE PERFORMANCE
Jennifer Lawrence - 'The Hunger Games'
BEST MALE PERFORMANCE
Josh Hutcherson - The Hunger Games'
Shailene Woodley -'The Descendant'
BEST COMEDIC PERFORMANCE
Melissa McCarthy - 'Bridesmaids'
'Harry Potter and the Deathly Hallows: Part 2'
BEST ON-SCREEN TRANSFORMATION*
Elizabeth Banks - 'The Hunger Games'
Jennifer Lawrence and Josh Hutcherson vs. Alexander Ludwig - 'The Hunger Games'
Robert Pattinson and Kristen Stewart - 'The Twilight Saga: Breaking Dawn - Part 1'
BEST GUT-WRENCHING PERFORMANCE
BEST ON-SCREEN DIRTBAG
Jennifer Aniston - 'Horrible Bosses'
'Party Rock Anthem' LMFAO - '21 Jump Street'