Signed up by Lieutenant John Devereaux of the Louisiana Artillery, Macheca became a private in Gomez's Company of the 22 Louisiana Infantry, Camp Lewis near New Orleans. At that time, it was thought that the war would be over quickly. Macheca's enlistment was for just nine months.
Macheca's term of service concluded just after the federal capture of New Orleans and just before the 22nd Regiment saw serious action. After leaving the army, he is known to have participated in black market activities during the federal occupation of the city and is believed to have helped run the Union blockade of southern ports.