Baylon will focus on driving AOL's relationships with major and independent holding companies, as well as agency trading groups.
He joins from Starcom MediaVest Group, where he has held a number of roles spanning all advertising channels over the past 14 years, most recently as head of trading.
He will report to Noel Penzer, managing director of AOL UK.
Baylon's appointment follows AOL launching its premium video platform AOL On in the UK, which it hopes will tap into traditional TV budgets.
He said: "I'm looking forward to taking AOL's precision and content marketing offering to our partners in the agencies and joining a management team who have a successful and winning formula."