NEW YORK — Bill Herz, the last surviving crew member of Orson Welles’s mock “War of the Worlds’’ newscast, which terrified American radio listeners in 1938 with vivid bulletins warning Newark residents to evacuate as invading Martians incinerated central New Jersey, died May 10 in Manhattan. He was 99.

The cause was complications of pneumonia, said Bill Kux, a cousin.

Mr. Herz, who worked on other radio and theater productions as stage manager and casting director for Welles’s Mercury Theater company, staked one additional claim to fame. Until about six months ago, he had been a regular customer at Sardi’s restaurant, the caricature-bedecked gathering place for celebrities and starry-eyed tourists in the theater district, for some 82 years — beginning in 1933, six years after it opened.

That longevity alone distinguished him as a bon vivant in a shrinking cadre of original Broadway personalties. But he was also singled out periodically in the wider world as a relic of a bygone era, when a bogus radio news broadcast could provoke panic as war was brewing in Europe — however much that hysteria may have been overstated then and since.

Welles’s CBS show “The Mercury Theater on the Air’’ presented an adaptation of the H.G. Wells novel “The War of the Worlds’’ for its Halloween episode on Sunday, Oct. 30, 1938. The live hourlong program began with an updated prelude to the original novel eerily warning that superintelligent beings had been coveting “this Earth with envious eyes.’’

Then music, a weather report, and other regular features were interrupted by simulated news bulletins and fake feeds from ham-radio operators in the field. Mr. Herz, playing Operators Three and Five, took part in this exchange:

Operator Three: This is Newark, New Jersey. … This is Newark, New Jersey. … Warning! Poisonous black smoke pouring in from Jersey marshes. Reaches South Street. Gas masks useless. Urge population to move into open spaces. … Automobiles use Routes 7, 23, 24. … Avoid congested areas. Smoke now spreading over Raymond Boulevard. …

Operator Four: 2X2L … calling CQ … 2X2L … calling CQ … 2X2L … calling 8X3R … Come in, please. …

Operator Five: This is 8X3R … coming back at 2X2L.

Operator Four: How’s reception? How’s reception? K, please. (Pause.) Where are you, 8X3R? What’s the matter? Where are you?

John Houseman, Welles’s producer, wrote in his 1972 memoir, “Run-Through’’: “Our actual broadcasting time, from the first mention of the meteorites to the fall of New York City, was less than 40 minutes. During that time men traveled long distances, large bodies of troops were mobilized, Cabinet meetings were held, savage battles fought on land and in the air. And millions of people accepted it — emotionally if not logically.’’ (Houseman went on to a distinguished career in theater and Hollywood.)

Mr. Herz also read Welles’s part, that of a Professor Pierson at a New Jersey observatory, during rehearsals. He said he was surprised by the public’s response to the radio show.

“During the broadcast, outside, policemen were coming,’’ he told CBS News in 2013. “They were told on the radio that the Martians were coming, the Martians were coming!’’ In a 2010 profile in The New York Times, Mr. Herz was quoted as saying: “I had done Orson’s part in the dress rehearsal, and after I did it, I thought to myself, ‘Nobody’s going to believe this in a million years.’ Boy, was I wrong.’’

William Herz Jr. was born in Detroit on Aug. 2, 1916, the son of Harold William Herz, a girdle salesman, and the former Fannie Lichtig. (Bill Herz called himself Jr., even though he wasn’t one.)

He graduated from the Carnegie Institute of Technology (now Carnegie Mellon University) in Pittsburgh before moving to New York.

He was briefly married to Susanne Guettel, whose brother Henry was a producer and film executive. No immediate family members survive.

Mr. Herz had met Welles in Pittsburgh, where Welles, a young director at the time, had stopped while touring with a production of “Romeo and Juliet.’’

They discovered that they had a common acquaintance in actress Edith Meiser, a friend of Mr. Herz’s parents.

Mr. Herz started working for Welles as a gofer. He later moved into Welles’s Manhattan home — Mr. Herz had been living with an aunt in Brooklyn — so that he could constantly be on call. They worked together on “Julius Caesar,’’ “The Cradle Will Rock,’’ and “Too Much Johnson.’’

Mr. Herz joined the Army Air Forces during World War II, managed a summer theater in Connecticut, and produced and managed several plays in New York (including a few flops, one inauspiciously titled “The Strangler Fig’’).

After one failure, Vincent Sardi Sr., founder of Sardi’s, generously invited him to keep an open tab in good times and bad. Another advantage to eating there was that Mackey’s Ticket Agency next door, where Mr. Herz later worked, had no restroom.

Ivan Lesica, Sardi’s maître d’hôtel, said Thursday that Mr. Herz would eat there once or twice a week and sit at Table Four, to the left of the dining room entrance, under his caricature. He would have coffee delivered in his own white mug, and typically order the chicken potpie or, appropriately enough for an habitué whom his cousin described as a confirmed curmudgeon, the crab meat sandwich.