The former Toledo businessman had been charged with engaging in a pattern of corrupt activity and six counts of tampering with records for scheming with former Toledo Public Schools Business Manager Daniel Burns to defraud the district of more than $650,000 between 2002 and 2006.
Judge James Bates accepted his plea and scheduled sentencing for Feb. 8.
Briggle is currently serving a two-year sentence from Lucas County for thefts from Toledo Hospital and a four-year sentence from Cuyahoga County for a similar scheme with Burns in the Cleveland Metropolitan School District.
Authorities said Briggle's printing company, Superior Offset Supplies, billed for thousands of dollars' worth of supplies and services that were never delivered.
On Monday, Burns, 55, entered an Alford plea in Lucas County Common Pleas Court to one count each of engaging in a pattern of corrupt activity, theft in office, and tampering with records. He is to be sentenced Jan. 4 by Judge Ruth Ann Franks.
In an Alford plea, the defendant maintains his innocence but pleads guilty to avoid going to trial and risking the possibility of a much longer prison sentence.