On February 20, 1868.
Lincoln's Secretary of War was Edwin M. Stanton. He had contested with Lincoln for the Republican nomination for President in 1860.
Johnson tried to remove war secretary from office but he refused it. The secretary was known as Edwin Stanton and has also served as the war secretary under Lincoln's regime.
Andrew Johnson was impeached after he fired Secretary of War Edwin M. Stanton, violating the Tenure of Office Act.
The main impeachment charge against President Johnson was that he'd violated the 1867 Tenure of Office Act by attempting to remove Secretary of War Edwin Stanton from office without the consent of the Senate.
The House of Representatives brought eleven articles of impeachment against President Andrew Johnson, most related to the violation of the Tenure of Office Act that occurred when Johnson attempted to remove Secretary of War Edwin M. Stanton from office.
Yes, President Andrew Johnson was directly involved with the Tenure of Office Act. He clashed with Congress over the Act, which was passed to restrict his ability to remove certain officeholders without Senate approval. Johnson violated the Act by dismissing Secretary of War Edwin Stanton, leading to his impeachment trial.
Johnson's big problems with Congress erupted when he fired the Secretary of War, Edwin Stanton. Stanton refused to vacate his office and barricaded it up for about two months until finally resigning after Johnson was acquited of impeachment charges.
After the Civil War, the former Confederate states were divided into military districts under the First Reconstruction Act of 1867. Secretary of War Edwin Stanton, naturally, chose the generals in charge of the various districts and was in a crucial position for how to carry out Reconstruction policies. Because Stanton and President Andrew Johnson had differing views on how to carry out the Reconstruction Act(s)--Stanton approving the Congressional means of restoring the nation, while Johnson followed his own route--some personal and professional animosity developed between the two. Furthermore, Johnson sought to establish himself and the office of executive as supreme over the legislature after their many quarrels over Reconstruction. Johnson decided to defy the Tenure of Office Act, which required the Senate's approval to remove government officials including the president's cabinet--an act which limited the president's power by Congress. Ultimately it was Stanton who, because of his differences in political opinion, his position as Secretary for the Department of War, and as a means by which Johnson could assert his authority, was fired in 1867. An act which would lead to the United States' first ever presidential impeachment.
President Andrew Johnson ignored the provisions of the Tenure of Office Act. Under the terms of the act, the President needed Senate approval to remove certain officials from office. President Johnson tried to fire Edwin Stanton, the last Radical Republican in his cabinet. The House voted to charge Johnson with wrongdoing in office, for trying to fire Stanton.
There was no President of the United States that was impeached for firing his Secretary of State. Perhaps you mean Andrew Johnson, the 17th President of the United States from 1865-1869, who was impeached for removing Edward Stanton, the Secretary of War. This violated a recently passed law, the Tenure of Office Act, which stated that the President couldn't remove cabinet members from their positions. The law was also quite unconstitutional, and was passed for the sole purpose of finding a reason to impeach Johnson, who was unpopular with the Republican Party. Although Johnson was impeached, he was later acquitted, and retained the office of the presidency until the next election cycle, when he chose not to run.
Simon Cameron was President Lincoln's first secretary of war. Lincoln became upset with Cameron when in early 1862, he distributed a report that urged the government to arm former slaves. Lincoln sent him to Russia as the US ambassador. Lincoln then appointed Edwin Stanton as the new secretary of of war.
President Andrew Johnson faced impeachment for attempting to remove Stanton from office. It was ruled unclear whether he violated the act.