Velocity was created by accident by the great inventor Wheeljack one dark and fateful night. Intending to make a bot that could teleport great distances, even between planets (much like an augmented version the Decepticon SkyWarp), another experiment-gone-wrong ended in something terribly right. Rather than traveling through space, Velocity was created with the ability to travel through time.
Unknowing of what he had done, Wheeljack sent his creation on a test run, the objective being the continent of Europe. However, since his abilities were not what anyone thought, Velocity ended up 20 Earth years in the future, and Wheeljack had already perished in the war. Confused and alone, he began recklessly skipping back and forth through time, attempting to find his creator once more.
After jumping through different time period for over three years in his own time, Velocity finally found his way to Wheeljack only moments after his own disappearance. The next 20 Earth years were spent fighting alongside his creator for the Autobot cause, until he was taken out in battle, leaving Velocity alone once more. He spent his next 100 years hopping around to different time periods once more, this time for his own entertainment.
After a while, he decided to pick a true destination. Recalling his "father" mentioning a time period that sounded interesting, Velocity set his course for the year 2009.