The 19-year-old Moate fighter had been widely expected to move into the paid ranks after controversially failing to qualify for this summer's Olympics despite winning the 2011 European crown.
But Ward has instead joined compatriot John Joe Nevin in committing to the first season with the Lionhearts team, where he will join the likes of Olympic silver medallist Fred Evans and Evans' fellow Welshman Andrew Selby.
Ward said: "Non-qualification, particularly in the circumstances, was a huge setback but the Olympic disappointment is firmly behind me now and I am looking forward to the future with a lot of hope.
"The WSB format is totally different in that the bouts are more regular so I will have to maintain my fitness levels. Only top boxers are invited to participate so clearly the improved standard will be of benefit."
Ward took his bid to reach London to the Court of Arbitration for Sport after losing a hotly disputed decision to Turkey's Bahram Muzaffer in the final Olympic qualifier. Meanwhile a place was awarded to Montenegro's lower-ranked Ratko Draskovic.
Ward will open his WSB account against Hungarian Imre Szello, whom he beat en route to winning his European title at the age of just 17. The GB Lionhearts began their campaign last week with a win over the USA Knockouts in California.
While Ward has signed up to the series until either February or May, depending on how the Lionhearts fare, he is keeping his options open as regarding his longer-term plans with professional promoters inevitably circling.
Ward added: "My plan for the immediate future is to remain amateur and hopefully defend my Irish senior title in February. I am committed to the GB Lionhearts until at least the end of February, and until early May if the team is successful.
"It is fair to say I have a number of opportunities available to me at present but neither I nor my team are yet prepared to look too far into the future. For now I am concentrating on my first fight for the Lionhearts."