David Hans Arntson, 62, of Newport Beach, California, agreed to enter a guilty plea in US District Court this week.
Under the terms of the plea agreement unveiled Tuesday, he will serve one year and a day in federal prison, followed by three years of supervised release, according to the plea agreement obtained by CNN.
In 2014, Arntson flew two Alaska Airlines flights, the first leg from San Diego to Portland, Oregon, followed by a second trip from Portland to Orange County, California, according to the criminal complaint.
When he landed in Orange County, he was selected for random drug and alcohol testing, according to a statement from the US Attorney's Office.
A technician for Alaska Airlines performed two breathalyzer tests that showed Arntson had a blood alcohol concentration of 0.134% and 0.142% -- well above the federal limit of 0.04% for pilots.
"The evidence indicates that he had flown with an alcohol level more than three times the legal limit," US Attorney Nicola T. Hanna said in a statement. "Thankfully, Mr. Arntson was never involved in an accident, but his conduct could have resulted in tragic consequences."
His attorney, Dyke Huish, said Arnston had a perfect safety record over his nearly 30-year career, and never tested positive for alcohol before that incident.
Arnston had worked for Alaska Airlines since 1987, along with Jet America prior to its merger with Alaska Airlines, Huish said.
After the June 2014 incident, Arntson retired from Alaska Airlines, and the Federal Aviation Administration revoked his pilot's license, the US Attorney's Office said.
He will be sentenced this spring in US District Court in Santa Ana, California, according to the attorney.
CNN has reached out to Alaska Airlines for comment.