By 1920, after Siegel received a "less than honorable" discharge from the Navy, he continued to work as a driver.
Later, it is believed Siegel worked as an ironworker on the Brooklyn Bridge or simply a bridge in Brooklyn, according to family.

In May 1929 Siegel wrote to the Navy and requested they give him a 3rd enlistment.
 He was unsuccessful in his plea.
 He was living at the Hotel Delaware in Milwaukee, Wisconsin.

Around 1930, Siegel abandoned his wife and daughter and headed to Oklahoma to work in the oil fields.
They never divorced and he started a new life, never having any contact with them again.

In 1935, Siegel is found to be in Lavagas (believing it to be Las Vegas) per the 1940 Census records, and in 1940, Siegel is found in Baltimore, Maryland, working as a lineman in a shipyard and living with his second wife, 20 years his younger, Mary Lou Siegel from Henryetta, Oklahoma.

On 28 May 1935 the New York chapter of the Red Cross wrote a letter on behalf of John Otto Siegel to the Bureau of Navigation, Navy Department, Washington D.C. requesting a duplicate Medal of Honor be issued.
The letter states that in November 1934 John was employed as an "Iron Worker" on the Boulder Dam project, in the "Death Valley Junction" of Nevada and that during this time a fire swept through the camp, believed to be Williamsville (known to its inhabitants as Ragtown) destroying all his belongings including his medal and service documents.
On June 17, 1935 the Bureau replied with instruction on how to apply for a replacement medal.

On 26 November 1936 Siegel made another request that the Navy allow him to reenlist.

On 5 and 16 April 1941 Siegel wrote to the Navy requesting a replacement Medal of Honor and ribbon bar pin or at least a letter stating he was the holder of the Medal of Honor or a new station.
 He stated it was lost in a home fire.
His return address is listed as 110 Madison Street San Antonio, Texas.
 On 31 July 1941 his request is denied due to his dishonorable discharge and his previous replacement medal was sent contrary to existing instructions due to same.
 His ruling is compared to the Judge Advocate General's ruling on Medal of Honor nominee William Henry Jaeger, for actions 16 July 1900; with two less than honorable discharges he was approved for the Medal of Honor but the medal was not to be delivered.

On 25 April 1942 Siegel filed a World War II Registration Card under the name John Robert Siegel, born in New York City.
 (In prior official documents John Otto Siegel stated his birth location as Berlin, New York as well as Milwaukee, Wisconsin.)
John Robert is living at Hotel London in Janesville, Wisconsin and working in Tulsa, Oklahoma with Mary Lou "someone from Henryetta, Oklahoma".

In 1943, Siegel died in Gary, Indiana of lung cancer at the age of 51.
 The front of the his death certificate shows his middle initial as "O" and the reverse of the document has his middle initial as an "R".
 He is buried in Mount Mercy Cemetery in Gary, Indiana.

Social Security Application and Claims Index, 1936–2007 show Jack Atto Siegel and John Robert Siegel are the same person.
The name change or modification is not explained.

Signatures from official documents of John Otto Siegel and John Robert Siegel show interesting similarities such as the "."
placed after each individual name or initial.
 The change in the "S" is also the same between the 1941 request for a replacement Medal of Honor and the 1942 World War II Registration card.


No other documents are found for anyone named John Robert Siegel or Jack Atto Siegel, that have any matching information, outside of these documents.
By 1920, after Siegel received a "less than honorable" discharge from the Navy, he continued to work as a driver. Later, it is believed Siegel worked as an ironworker on the Brooklyn Bridge or simply a bridge in Brooklyn, according to family.
In May 1929 Siegel wrote to the Navy and requested they give him a 3rd enlistment.  He was unsuccessful in his plea.  He was living at the Hotel Delaware in Milwaukee, Wisconsin.
Around 1930, Siegel abandoned his wife and daughter and headed to Oklahoma to work in the oil fields. They never divorced and he started a new life, never having any contact with them again.
In 1935, Siegel is found to be in Lavagas (believing it to be Las Vegas) per the 1940 Census records, and in 1940, Siegel is found in Baltimore, Maryland, working as a lineman in a shipyard and living with his second wife, 20 years his younger, Mary Lou Siegel from Henryetta, Oklahoma.
On 28 May 1935 the New York chapter of the Red Cross wrote a letter on behalf of John Otto Siegel to the Bureau of Navigation, Navy Department, Washington D.C. requesting a duplicate Medal of Honor be issued. The letter states that in November 1934 John was employed as an "Iron Worker" on the Boulder Dam project, in the "Death Valley Junction" of Nevada and that during this time a fire swept through the camp, believed to be Williamsville (known to its inhabitants as Ragtown) destroying all his belongings including his medal and service documents. On June 17, 1935 the Bureau replied with instruction on how to apply for a replacement medal.
On 26 November 1936 Siegel made another request that the Navy allow him to reenlist.
On 5 and 16 April 1941 Siegel wrote to the Navy requesting a replacement Medal of Honor and ribbon bar pin or at least a letter stating he was the holder of the Medal of Honor or a new station.  He stated it was lost in a home fire. His return address is listed as 110 Madison Street San Antonio, Texas.  On 31 July 1941 his request is denied due to his dishonorable discharge and his previous replacement medal was sent contrary to existing instructions due to same.  His ruling is compared to the Judge Advocate General's ruling on Medal of Honor nominee William Henry Jaeger, for actions 16 July 1900; with two less than honorable discharges he was approved for the Medal of Honor but the medal was not to be delivered.
On 25 April 1942 Siegel filed a World War II Registration Card under the name John Robert Siegel, born in New York City.  (In prior official documents John Otto Siegel stated his birth location as Berlin, New York as well as Milwaukee, Wisconsin.) John Robert is living at Hotel London in Janesville, Wisconsin and working in Tulsa, Oklahoma with Mary Lou "someone from Henryetta, Oklahoma".
In 1943, Siegel died in Gary, Indiana of lung cancer at the age of 51.  The front of the his death certificate shows his middle initial as "O" and the reverse of the document has his middle initial as an "R".  He is buried in Mount Mercy Cemetery in Gary, Indiana.
Social Security Application and Claims Index, 1936–2007 show Jack Atto Siegel and John Robert Siegel are the same person. The name change or modification is not explained.
Signatures from official documents of John Otto Siegel and John Robert Siegel show interesting similarities such as the "." placed after each individual name or initial.  The change in the "S" is also the same between the 1941 request for a replacement Medal of Honor and the 1942 World War II Registration card. 

No other documents are found for anyone named John Robert Siegel or Jack Atto Siegel, that have any matching information, outside of these documents.
John Otto Siegel