Mohegan — A rarity among high school seniors, Sarah Harris had a clear idea where her college education would lead.

At 17, her Dartmouth acceptance in hand, she told a reporter she planned to major in government and Native American studies — “and bring my knowledge back to help my tribe.”

That was 22 years ago.

On Monday, Harris will take an oath of office as the newest member of the Mohegan Tribal Council, the nine-member body that governs the tribe and serves as the management board of its increasingly far-flung gaming enterprise, Mohegan Gaming & Entertainment.

She's made good on her promise.

“I remember growing up, when we were getting federal recognition, it’s what tribal members always talked about: taking advantage of scholarships, following dreams and bringing your experience back home,” Harris said in a recent interview. “That’s what nation-building is. It was always my plan.”

Harris doubled down on education, earning her bachelor’s degree at Dartmouth in 2000 and a law degree from American University’s Washington College of Law in 2005. A decade of service to Indian tribes followed, first in private practice and then in government, culminating in her two-and-a-half year stint as chief of staff to the U.S. Department of the Interior’s assistant secretary for Indian affairs.

After leaving the Interior Department in 2015, she joined a law firm, representing tribes and tribal organizations. In November 2016, the National Center for American Indian Enterprise Development recognized her as one of 40 emerging Native American leaders under the age of 40.

“I just squeaked in,” said Harris, who turned 39 a couple of months after receiving the honor.

Back living in her native Griswold with her 16-month-old twins — a boy and a girl — Harris said she might have returned to Mohegan earlier, were it not for election outcomes. She ran unsuccessfully for the tribal council in 2007 and 2010. (Her father, Roland Harris, a former Griswold first selectman, served on the tribal council from 1995 to 2006 and was council chairman from 1995 to 2000.)

Harris won election in balloting among tribal members that concluded Aug. 27. Four incumbents who were up for re-election also won four-year terms. The council will elect officers following Monday's swearing-in ceremony.

It was soon after her second failed council bid that Harris went to work for the Department of the Interior, first in the Office of the Solicitor and then as chief of staff to the department’s assistant secretary for Indian affairs, an office then held by Kevin Washburn. In the latter post, she managed about 8,000 staff, including the Bureau of Indian Affairs and the Bureau of Indian Education.

Harris advised then-Interior Secretary Sally Jewell on a wide range of Indian policy issues, collaborating with the White House and federal agencies on, among other things, implementation of President Barack Obama’s drive to increase trust lands held by tribes, promulgation of Indian Child Welfare Act regulations and the issuance of numerous decisions affecting individual tribes.

Harris said it was rewarding “to work for a president who really cared” about tribes, and believes the Obama administration was the most favorable administration in history to Indian Country.

In late November 2016, after Democratic candidate Hillary Clinton's election defeat, Harris and 16 other Native American appointees who had served in Obama’s administration signed a letter urging him to block or reroute the Dakota Access oil pipeline, a project considered a threat to the Standing Rock Sioux Tribe’s North Dakota reservation. Near the end of Obama’s term, the Army Corps of Engineers announced it would look for alternative routes for the pipeline, a process President Donald Trump cut short upon taking office.

The Trump administration’s approach to other tribal issues, such as tribal sovereignty and tribal land ownership, also has differed from that of the previous administration, Harris said.

“Indian Country is constantly under assault,” she said. ”There’s always this push and pull, the challenge of state and federal governments’ overreach into tribal affairs.”

Ironically, the Mohegans, partners with the Mashantucket Pequots in a commercial casino venture, currently are dealing with the very federal office Harris used to serve, that of the assistant secretary for Indian affairs. In a Sept. 15 letter, Michael Black, the acting assistant secretary, created some doubt about the office’s consideration of the tribes’ amended gaming agreements with the state of Connecticut.

Black wrote that Interior Department action on the amendments “is premature and likely unnecessary,” a response the Mohegans have interpreted as tantamount to approval.

Harris, who said she had to recuse herself from discussing matters directly involving her tribe while she was working for the department, declined to comment on that issue.

b.hallenbeck@theday.com