Sen. Frank Lautenberg (D-N.J.), who died on Monday of viral pneumonia, was the oldest member and last surviving WWII veteran of the U.S. Senate.

Known for his strong support of gun control, tobacco sale regulation and increased government spending on environmental infrastructure, the New Jersey Democrat was a member of the United States Army Signal Corps from 1942 to 1946, according to biographical information released by his office.

In 2010, Lautenberg became the oldest member of the Senate following the death of Sen. Robert Byrd (D-W.V.), who was then the longest-serving U.S. senator.

"We had some good fights over our time - battles on philosophy and the role of government," said New Jersey Republican governor Chris Christie at a GOP event, according to CNN.

"I think the best way to describe Frank Lautenberg and the way he would probably want to be described to all of you today is as a fighter. Senator Lautenberg fought for the things he believed in and sometimes he just fought because he liked to."

Christie is expected to appoint an interim replacement until a special election is held, according to New Jersey state law.

Lautenberg missed out on crucial Senate votes last year, for several weeks, as he was battling stomach cancer and what he believed at the time was bronchitis.

He also announced in a statement last February that he would not seek reelection next year because of his deteriorating health.

Lautenberg was also expected to shore up legislation in the Senate that would mandate background checks for sales of explosive powders, according to CNN.