First-time candidate Matt Shaheen narrowly defeated Collin County Commissioner Phyllis Cole in the Republican primary runoff Tuesday.

Mr. Shaheen, who won by 30 votes, faces no Democratic opponent in the November general election. He will begin his four-year term on Jan. 1.

Mr. Shaheen called for tax cuts, reduced spending and term limits for commissioners. Ms. Cole, who has represented Precinct 1 for 18 years, touted her experience.

“I’m elated,” said Mr. Shaheen, a technology professional. “I think people wanted some fresh ideas and new approaches to governing the county.”

Ms. Cole said she had no regrets about her campaign. She called to congratulate Mr. Shaheen as soon as the votes were final.

“When you get in a runoff, it’s all a matter of turning out your vote,” Ms. Cole said. “He did a better job than I did.” Mr. Shaheen had the endorsement of County Judge Keith Self, who heads the five-member commissioners court. “I think it made a huge difference,” Mr. Shaheen said of his support.

Ms. Cole had the backing of the three other commissioners: Jack Hatchell, Jerry Hoagland and Joe Jaynes.

“We’ve done a lot of things, the four of us working together,” said Mr. Cole, 61. “I’m very proud of all the programs we’ve started.”

Precinct 1 covers west Plano and parts of Frisco.

Mr. Shaheen, 42, said he entered the race because the Republican Party had strayed from the “core principles of Ronald Reagan.”

Ms. Cole said she was a fiscal conservative, too. During her tenure, the court has reduced the property tax rate twice.

Mr. Shaheen criticized Ms. Cole for not supporting a tax cut in the current $265 million budget. She joined other commissioners in supporting a $328 million bond election, which passed handily in November.

Mr. Self, who won election two years ago, opposed the bond issue, as did Mr. Shaheen.

Mr. Shaheen said he supports some of the judge’s views but wouldn’t mirror his votes.