Way back in March it was revealed that John Malkovich signed on to the cast of Transformers 3 and yet the only detail learned was the character was the boss of Sam. Finally, in a interview with Hit Fix to promote Secretariat, the actor finally added a few small details including the name of the character as Bruce Brassos. Based on the description he is essentially playing the equivalent of the Rainn Wilson character from Transformers 2. If watch the video, the TF3 portion starts at 2:15.
A newcomer to the series, Malkovich plays the boss of our hero Sam (the always present Shia LaBeouf) and said he was subject to only one day of action. And he bluntly and slyly describes his "loudmouth" character as, well, a "jerk." He also volunteers he had a "very, very enjoyable time" shooting with John Turturro, Rosie Perez and LaBeouf. Malkovich ends with, "For me, it was a blast."