LEESBURG, Va. – Loudoun United FC has announced the signing of forward Thorleifur Úlfarsson and defender Salvatore Mazzaferro each to two-year contracts through the 2027 USL Championship season. The transactions are pending league and federation approval.

Úlfarsson having most recently competed for Breidablik in his native Iceland having previously competed in Major League Soccer for Houston Dynamo FC. The 25-year-old recorded seven goals and one assist for the Dynamo in 1,656 regular season minutes after being selected fourth overall in the 2022 MLS Super Draft.

“I’m excited for this new chapter and thankful for the opportunity,” said Úlfarsson. “I’m here to work hard, grow every day, and do whatever I can to help this team succeed. I promise I’ll give my all for the supporters and everyone in the club.”

Úlfarsson had previously delivered a standout collegiate career at Duke University where he earned ACC Offensive Player of the Year and All-Atlantic Coast Conference First Team honors. He finished his Duke career with 19 goals and helped lead the program to multiple postseason appearances.

“Thor brings physicality, intensity, and a team-first mentality that aligns with the standards we’re building at Loudoun United,” said Loudoun United Sporting Director Alen Marcina. “He’s a relentless competitor with a high ceiling, and he has the attributes to make a real impact in our attack. His presence, work rate, and edge add an important dimension to our group and give our supporters something to be excited about.”

Mazzaferro joins United having most recently competed in MLS NEXT Pro with Atlanta United 2, where he recorded three goals and one assist in 27 appearances in the 2025 campaign. The 24-year-old center back also won 95 duels at a 59.7 percent success rate and made 106 recoveries and 24 interceptions defensively.

“Joining Loudoun United is the start of an exciting challenge and a fresh chapter in my journey. I’m ready to give it my all – bringing energy, discipline, and a strong work ethic to every training session and match,” said Mazzaferro. “I’m committed to improving every day, supporting my teammates, and pushing myself to help the club succeed both on and off the field. This is our year!”

Mazzaferro performances earned him opportunities with Atlanta United, for which he made two appearances – one in a Leagues Cup match against Mexican side Atlas and an MLS regular season contest against Inter Miami CF. A native of Toronto, Canada, Mazzaferro began his professional career in the Austin FC organization after being selected in the Third Round of the 2023 MLS SuperDraft. He signed with Austin FC II in MLS NEXT Pro in March 2023 and went on to make more than 50 appearances for the club.

Mazzaferro was part of the Austin FC II squad that won the 2023 MLS NEXT Pro Cup, adding postseason experience to his resume early in his career.

“Sal is a left-footed center back who brings leadership, composure, and presence to our back line,” said Marcina “He’s served as a captain, is comfortable progressing the ball, and plays with a competitive edge and professionalism that stand out. He’s hungry to keep pushing his level in a demanding environment, which aligns well with the identity and standards we’re building at Loudoun United.”