Eileen F. Skinner, Mercy Hospital’s longtime president and chief executive officer, has tendered her resignation effective March 31.

Skinner’s resignation was announced Monday in a news release from Mercy’s parent organization, Brewer-based Eastern Maine Healthcare Systems. Skinner has been employed by Mercy since September 2002. Mercy was acquired by EMHS in 2013.

During her tenure, Skinner oversaw the construction of a new state-of-the-art hospital along the Fore River in Portland.

She earned just over $1 million in compensation during the one-year period from October 2013 to September 2014, according to tax Form 990, filed with the federal government.

“I need a break,” Skinner replied when asked Monday in a telephone interview about her reasons for leaving.

For more than 13 years, Skinner has led Mercy, which operates six primary care facilities, five express care sites, and 22 specialized physician practices in southern Maine. “I tell people I am going home and take a nap.”

Mercy Hospital joined EMHS after a deal to merge with Steward Health Care Systems, a for-profit health care company in Boston, fell through. The two sides had signed a letter of agreement in August 2012, but six months later the merger was terminated. At the time, Mercy did not say what went wrong in its negotiations.

Instead, Mercy signed a letter of intent with EMHS, a health care system that encompasses seven hospitals, nine nursing homes, and retirement communities in eastern and northern Maine.

Four years after Skinner arrived, Mercy embarked on an ambitious expansion on its 42-acre Fore River campus. The $162 million expansion project featured a five-story, 150,000-square-foot hospital, which opened in 2008.

Mercy expects to close its State Street hospital and relocate its operations to the Fore River campus by no later than 2018. The State Street hospital opened in 1943. Its precursor – called Queen Anne’s Hospital – opened in 1918 at State and Congress streets after city hospitals refused to treat Irish Catholic patients during the 1918 flu pandemic.

M. Michelle Hood, president and CEO of EMHS, credited Skinner with “bringing life to Mercy’s vision to locate a state-of-the-art hospital along the Fore Fiver.”

Hood said Skinner helped Mercy make the transition to its new parent organization in 2013 while developing a Greater Portland network of primary and specialty care programs.

“She is known as a strong advocate for the Mercy mission to provide service to the community and the poor and the disadvantaged. We are appreciative for the dedicated service, strategic value and organizational skills she has brought to Mercy,” Hood said in a statement.

Mercy is a not-for-profit organization that is sponsored by the Sisters of Mercy of the Americas.

Chris Howard, chairman of Mercy’s board of directors, said southern Maine has benefited from Skinner’s commitment to quality service and care.

“Eileen has been instrumental in guiding Mercy Hospital through more than a decade of dynamic change as the hospital has kept pace with the rapid pace of developments in the health care industry,” Howard said in a statement. “I would be remiss if I did not mention her steadfast commitment to the Sisters of Mercy and the mission of Catholic healthcare.”

Skinner, who lives in Falmouth, moved to Maine from New Orleans. She says she will miss the people she had the opportunity to work with.

“I cannot thank them enough for their devotion to the mission and their hard work. I have learned much more from them and their daily inspiration than they ever learned from me. I will take that knowledge and inspiration into my next career endeavor,” Skinner said.

A search for Skinner’s replacement will begin immediately.