State Representative Byron Rushing, the House assistant majority leader and the fourth-highest ranking Democrat in the House, was defeated by Jon Santiago, a Boston Medical Center emergency medicine resident. In a three-person race, Santiago received 48 percent of the vote to Rushing’s 37 percent.

In a pair of major upsets, two longtime state representatives and high-ranking Democrats were unseated in Tuesday’s primary election, according to unofficial results.

Representative Byron Rushing was ousted in an upset by Jon Santiago.

State Representative Jeff Sánchez, a Jamaica Plain Democrat and the House Ways and Means chairman, was defeated, 52 percent to 48 percent, by Nika Elugardo, who has worked for a number of state and local advocacy organizations.


Sánchez, 49, was first elected in 2002 and hadn’t faced a primary opponent since 2010. His district includes Jamaica Plain, Mission Hill, Roslindale, and part of Brookline. Elugardo had criticized Sánchez’s priorities and described herself as “super left,” while saying Sánchez was not progressive enough to represent the district.

Elugardo, 44, grew up in Ohio and received degrees from the Massachusetts Institute of Technology, Harvard University’s Kennedy School of Government, and Boston University Law School.

Rushing, 75, was first elected in 1982. His district includes most of the South End, spanning from Fenway and Back Bay to Roxbury. Santiago was born in Puerto Rico and moved to Boston when he was young. He is a former Peace Corps volunteer and won a Fulbright Scholarship to study in Paris.

In a phone interview Tuesday night, Santiago said he was excited and grateful for the victory. He added that he hoped to continue Rushing’s legacy.

“I think a lot of people said this couldn’t be done, that ‘You had no shot.’ A lot of people wrote me off in the beginning,” Santiago said.

Fighting the opioid crisis will be one of his main priorities as a representative, Santiago said.


“The community deserves more when it comes to the opioid issue,” he said.

Full election results were not available at Globe press time.

In other races, incumbent Stephen Murphy narrowly defeated challenger Katie Forde in the Democratic primary for the Suffolk register of deeds, 53 percent to 47 percent.

Forde, a family law paralegal, had run unsuccessfully against Murphy for the same position in 2016. Despite the position’s relatively low profile, the race intensified this year, with the candidates clashing on priorities over the six-year term.

In other primary races Tuesday:

■ US Representative Joe Kennedy III easily defeated challenger and longtime climate change activist Gary Rucinski in the Democratic primary for the state’s Fourth Congressional district. Kennedy received more than 90 percent of the vote.

■ US Representative Richard Neal, a 15-term incumbent, fended off a bid from Tahirah Amatul-Wadud in the First Congressional District. Amatul-Wadud is an activist lawyer from Springfield and a first-time candidate.

■ In the Fifth Congressional District, John Hugo defeated Louis Kuchnir in the Republican primary. The winner faces incumbent Representative Katherine Clark in November’s general election.

■ James McMahon defeated Daniel Shores to become the Republican nominee for attorney general. He will face Attorney General Maura Healey in November.

■ Longtime state Representative Liz Malia was reelected over two Democratic primary challengers, Charles Clemons Muhammad and Ture R. Turnbull.

■ State Representative Angelo Scaccia defeated four Democratic challengers: Segun Idowu, Christopher Obi Nzenwa, Virak Uy, and Gretchen Van Ness.


■ In the state Senate, candidates fought for the seat left vacant by former Senate president Stan Rosenberg, who resigned in May following sexual harassment accusations against his husband, Bryon Hefner.

Educational administrator Chelsea Kline was technically the only person who appeared on the ballot. Northampton City Council President Ryan O’Donnell, Central Hampshire Veterans’ Services Director Steven Connor, and progressive activist Jo Comerford all launched write-in campaigns to fill the seat.

■ State Senator Jason Lewis was leading Sam Hammar in the Fifth Middlesex District, which includes several cities and towns north of Boston.

J.D. Capelouto can be reached at jd.capelouto@globe.com. Follow him on Twitter @jdcapelouto.