He has not had a particularly high profile in New Jersey, a contrast with past attorneys general, who most often become household names because of controversies under their watch.
His selection Thursday was greeted warmly by Republican state lawmakers.
"Mr. Chiesa is a venerable public servant, devoted to protecting people from corruption and violence," said Sen. Kevin O'Toole, the minority whip, in a statement. "He is a smart, deliberative individual who will represent this state in Washington with honor and distinction."
Any initial complaints about the select weren't about Chiesa but his party.
"I have worked with Attorney General Chiesa on many issues over the last few years and believe he is capable of filling the seat. Still, New Jersey voters overwhelmingly re-elected Senator Lautenberg, so his replacement should have been a Democrat," said state Senate President Stephen Sweeney, a Democrat. "The will of the people should not have been ignored."
Christie said he'll appoint an acting attorney general on Monday and said there is no timetable to nominate a permanent replacement. He said it's unlikely that Chiesa will return to the position but did leave the door open to Chiesa returning to his administration in some capacity.
Christie has scheduled a special election for October to fill the seat until it expires in 2015. Whoever wins in October would have to run again in 2014 to keep the seat for a full six-year term.
The campaign for the special election is on a compressed schedule with a primary in August and general election in October.
On Thursday, U.S. Rep. Rush Holt became the first Democrat to announce he's seeking his party's nomination.
"I am the best candidate to continue the passionate advocacy for progressive values that Sen. Lautenberg exemplified," he wrote in an email to supporters.
Holt, now 64, was assistant director of the Princeton Plasma Physics Laboratory for most of the 1990s before being elected to Congress in 1998. Around his central New Jersey district, it's not uncommon to see a bumper sticker that proclaims, accurately: "My congressman IS a rocket scientist."
He's considered one of the most liberal members of New Jersey's congressional delegation. He's pushed for laws against racial profiling and has been critical of drilling for oil and natural gas on public lands and waters.
Two well-funded Democrats, U.S. Rep. Frank Pallone and Newark Mayor Cory Booker, had expressed interest in the seat before Lautenberg died, but neither has made an announcement.
The only Republican in the race so far is former Bogota Mayor Steve Lonegan, who has twice sought his party's nomination for governor.
Lonegan, who runs the state office for Americans for Prosperity, said Wednesday that he looks forward to weighing in on national issues such as the Obama administration's handling of the attack last year in Benghazi, Libya, and the selective scrutiny of conservative groups' nonprofit tax applications.