TRENTON -- Assemblyman John Wisniewski's announcement Tuesday he's launching a statewide bid to succeed Gov. Chris Christie could upend a Democratic primary that many considered over before it officially began.

Wisniewski, who gained national notoriety for spearheading the investigation into Christie's administration over the George Washington Bridge lane closures, declared he's challenging former banking executive Phil Murphy with hopes to become the state's 56th governor.

Here are five things to know about Wisniewski, a 54-year-old attorney from Sayreville who has served in the state Assembly for 21 years:

1. Transportation guru

As chairman of the Assembly's Transportation and Independent Authorities Committee, Wisniewski has devoted much of his time as a lawmaker to sponsoring transportation legislation. He had a hand in reshaping the state's then-Division of Motor Vehicles under the Motor Vehicle Security and Customer Service Act, opposed the recent gas tax hike because he said it set the state up for a long-term shortfall and pressed Christie on toll increases.

2. Bridgegate crusader

It was Wisniewski's time heading the transportation committee and his investigation into toll increases that ultimately led to the Bridgegate scandal becoming national news.

Wisniewski's panel subpoenaed the authority largely because it was probing the toll increases. After four days of gridlock in Fort Lee with rumors of punitive undertones became news in the state, the panel launched an investigation.

It joined forces with Senate lawmakers and together, the Democratic-controlled committee subpoenaed state officials that led to the infamous "time for some traffic problems in Fort Lee" email.

At the time, Christie was eyed as the favorite to lead the Republican Party into the 2016 presidential election.

Assemblyman John S. Wisniewski.

The story was national news and gave Wisniewski wide exposure.

And judging by the many images of the George Washington Bridge in his first campaign video, Wisniewski will likely remind New Jerseyans many times that he had a big part in leading to Christie's diminished standing on the national and statewide stage.

3. Bernie backer

As Democrats across the state and country lined up behind former Secretary of State Hillary Clinton in the Democratic primary, Wisniewski opted to throw his support behind underdog Bernie Sanders.

He served as chairman of Sanders' New Jersey campaign.

4. Party leader

Wisniewski has held leadership positions in the Assembly since he was elected in 1995, including spots as deputy speaker and his committee chairmanship.

He also led his party as Democratic state chairman for 3 1/2 years.

5. Outsider

Despite his time in leadership positions, Wisniewski enters the gubernatorial race as a bit of an outsider.

The state party, led by Chairman John Currie, voted behind closed doors earlier in the year to squeeze Wisniewski out of a position on the Democratic National Committee.

On the heels of Wisniewski's gubernatorial announcement, Currie issued a statement accusing him of being a "failed" lawmaker and reaffirmed his support for Murphy.

Matt Arco may be reached at marco@njadvancemedia.com. Follow him on Twitter @MatthewArco or on Facebook. Follow NJ.com Politics on Facebook.