He had reached the rank of Captain by that time and, that summer, he was appointed a provost marshal and assigned to New York City where he would oversee enforcing conscription in the Tenth District.

Although criticized for the low number of recruits compared to the other provost marshals in the city, Secretary of War Edwin M. Stanton defended Erhardt's efforts stating "The men he enlists may be few but they go to the front and fight, every one of them.

[1] In the days before the New York Draft Riots, he was confronted by several men with iron bars while trying to collect names in a new tenement building at Broadway and Liberty Street.

Erhardt held the men off for three hours while waiting for reinforcements, armed only with his pistol, but was eventually forced to retreat without the names.

He also became receiver of the New York City and Northern Railroad and, by 1888, the annual receipts of the road had risen from $24,000 to $400,000 when he returned control of the line to its owners.

Marshal, publicly endorsed his candidacy stating: One of seven candidates, it was suggested at the time that Erhardt had merely been placed on the ticket as a political sacrifice for the Republicans.

[1] In September 1909, Erhardt was staying at the Union League Club while his wife, Nora Belle Jewett, was visiting their daughter at York Harbor, Maine for part of the summer.

His family physician, Dr. John Solley, was called from his home on West Fifty-Eighth Street but Erhardt died at 1.20 a.m. At the time of his death, he was the president of the Lawyers' Surety Company and a director in a number of corporations.