[citation needed] On November 3, 1998, Paul Cellucci was elected as governor, narrowly defeating Democratic attorney general Scott Harshbarger.

[citation needed] Cellucci was a fiscally conservative, anti-tax governor who had the ability to work in a bipartisan fashion with an overwhelmingly Democratic State Legislature.

In 2001, the libertarian Cato Institute, in its fifth biennial fiscal policy report card,[6][7] gave Cellucci an "A" grade and said he "earned the distinction of having the best record of reducing taxes and restraining spending growth" among the nation's 50 governors.

Those standards, which required students to pass exams in basic Math and English to receive a high school diploma, were a major piece of the Education Reform Act of 1993 and were phased in over time.

The standards have remained in effect and in its June 4, 2007 report card on "No Child Left Behind," Time magazine found that Massachusetts students score the best on the federal tests.

[8] The biggest controversy during Cellucci's tenure was the huge cost overruns on the "Big Dig" – an enormous project to replace the elevated central artery highway in Boston with a tunnel.

[9] Cellucci appointed many women to high ranking positions, including Margaret H. Marshall as the first female Chief Justice of the Massachusetts Supreme Judicial Court.

On April 17, 2001, at the Citadel in Quebec City, Cellucci presented his credentials as the 27th United States Ambassador to Canada to Governor General Adrienne Clarkson.

On September 14, 2001, three days after the terrorist attacks on United States soil, Ambassador Cellucci thanked Canada for its overwhelming support and sympathy, including their role in Operation Yellow Ribbon, at a memorial in front of 100,000 people on Parliament Hill in Ottawa.

[10] This wording was considered especially unfortunate by some since the United States did in fact delay years before joining the British Empire in both World Wars I and II in Europe.

The Globe and Mail reported Cellucci's remarks under the front-page headline "U.S. rebukes Canada"[11] and Canadian nationalist Mel Hurtig called him "ill-mannered, obnoxious, [and] arrogant".

While each country retains all rights to do what is in its security interests, Cellucci believed that as a practical matter, this makes it highly unlikely that anything like the Arar situation will happen again.

Cellucci left Magna International in the fall of 2006 and joined the Boston office of the law firm of McCarter & English, LLP, where he held the title of Special Counsel.

In 2008, Cellucci said that, after thirty-five years in public service, he had no intention of seeking further office, and that, while he had no interest in serving as vice president, he did not exclusively rule it out.

[16] In 2013, Cellucci was a signatory to an amicus curiae brief submitted to the United States Supreme Court in support of same-sex marriage during the Hollingsworth v. Perry case.

[18] In January 2011, Cellucci announced he had been diagnosed with amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, and that it was progressing relatively slowly.

[19] Cellucci responded to his diagnosis by leading an effort to raise $10 million for research at the University of Massachusetts Medical School (UMMS) into amyotrophic lateral sclerosis.

I happened to know him in the realm of politics and government, but anyone who knew him in any other arena would have found the same man: a person of rock-hard integrity, keen intelligence, considerable humor, abundant compassion, and deep devotion to family and country.

I can attest to the fact he was a great friend to Canada, and we are grateful for his contributions to the bilateral relationship, both as ambassador and as governor of Massachusetts," said Canadian Foreign Minister John Baird.