He defeated Vince Polistina, a Republican Assemblyman.
Republicans took both Assembly seats. Incumbent John Amodeo and running mate Chris Brown defeated two Democratic challengers, assuring that the district will remain politically split.
The 2nd District battle was the most expensive in the state, with the candidates and their Assembly running mates combining to spend more than $3 million.
It was seen as one of the few legislative elections this year that could have gone either way.
Whelan is a teacher and former Atlantic City mayor who has been a state lawmaker since 2006. Polistina is an engineer who has been in the Assembly since 2008.