Chapman, who had vowed to appeal any suspension, said in a statement he would not appeal. The suspension starts when the regular season opens.
"I am gratified that Mr. Chapman has taken responsibility for his conduct," Commissioner Rob Manfred said in a statement, "that he has agreed not to appeal the 30-game suspension, and that he has agreed to comply with the confidential directives ... to ensure that a similar incident does not occur in the future."
The announcement of the suspension did not say what other disciplinary actions were taken. Under the policy, players can be required to submit to counseling, relinquish weapons and relocate from a home shared with a partner, among other options. Disciplinary action beyond a suspension is intended to be confidential.
Chapman is accusing of choking his girlfriend during a dispute at their Florida home and firing eight shots from a gun in the garage, according to a police report. Chapman acknowledged shooting the gun, but said, "I never hurt anyone."
In a statement Tuesday, Chapman said: "I want to be clear, I did not in any way harm my girlfriend that evening. However, I should have exercised better judgment with respect to certain actions, and for that I am sorry.
"The decision to accept a suspension, as opposed to appealing one, was made after careful consideration. I made this decision in an effort to minimize the distractions that an appeal would cause the Yankees, my new teammates and most importantly, my family."
After investigating the incident, authorities declined to file charges, citing conflicting and insufficient evidence, according to reports. Under baseball's domestic violence policy, introduced in August, the commissioner can levy discipline even if a player is not charged with a crime. Manfred said he had considered public documents, a staff report and an interview with Chapman.
"I found Mr. Chapman's acknowledged conduct on that day to be inappropriate under the negotiated policy, particularly his use of a firearm and the impact of that behavior on his partner," Manfred said.
The announcement caps one of the sport's three domestic violence investigations.
Dodgers outfielder Yasiel Puig is under investigation after a report that he hit his sister during a bar fight. No charges were filed.