Twice Burleigh opened up a 10-point lead over the Dolphins but a try from late Redcliffe inclusion Darren Nicholls 16 minutes into the second half narrowed the margin to just four points.
The two teams were locked in a tense duel for the next 10 minutes as the Dolphins looked for the go-ahead try but it was Cullen who capped a brilliant individual display with a try in the 70th minute that would ultimately seal their second Intrust Super Cup title.
Although Cullen was able to take advantage of a tiring defence late he challenged Redcliffe from the opening minutes of the match, laying on two tries for fullback Kurtis Rowe and having a hand in Sami Sauiluma's second-half four-pointer.
Nicholls and Broncos winger Jonus Pearson were important late inclusions for Redcliffe but it was Cullen and future Parramatta Eel Jamal Fogarty who not only put on the points but controlled the closing stages perfectly.
Burleigh's big men seemed to be wilting somewhat in the Brisbane heat to start the second term – Redcliffe centre Daniel Randall spilling a Zach Strasser bomb on the Bears' try-line – but Burleigh was first to score again, this time through Sami Sauiluma.
The combination of Cullen and Rowe down the left edge again pulled the Redcliffe defence enough to give the rampaging Sauiluma just enough to space to force his way over inside the left corner post and a 20-10 lead after 50 minutes.
Ruled out on Tuesday by Dolphins coach Adam Mogg with a quadriceps tear, Darren Nicholls had enough confidence to push off his right leg to challenge the Burleigh defence 17 minutes into the second half, slicing through to score to the right of the posts and then landing the conversion.
Cullen's left-foot step then exposed a tiring Redcliffe defence 12 minutes from full-time, slicing through between Aaron Whitchurch and Nicholls to extend Burleigh's lead to eight points, Jamal Fogarty putting them out by 10 points with eight to play with a successful conversion from wide out.