The 25-year-old Cameroon international, who penned a five-year contract with an option for an additional 12 months, described the move as joining "the club of my dreams."
The transfer, finalized after United's third offer of 65 million pounds plus 6 million pounds in add-ons, ended a seven-week saga that captivated fans. Mbeumo, who will wear the number 19 shirt, joins forward Matheus Cunha and left-back Diego Leon as part of manager Ruben Amorim's squad overhaul.
"I had to take the opportunity to sign for the club of my dreams, the team whose shirt I wore growing up," Mbeumo said. "My mentality is to always improve. I know I can reach another level here, learning from Ruben Amorim and playing with world-class players. The plans for the future are exciting, and we're determined to challenge for the biggest trophies."
Mbeumo's prolific record at Brentford, 70 goals and 51 assists in 242 appearances since 2019, made him a prime target. Last season, he hit career highs with 20 Premier League goals and seven assists. His departure surpasses Brentford's previous record sale of Ivan Toney to Al-Ahli for 40 million pounds in August 2024.
United's director of football, Jason Wilcox, praised the signing. "Bryan's goals and assists record is exceptional, and his consistency ranks him among England's most productive players over the last three seasons," Wilcox said.
"His belief in our project and determination to join confirmed he's the perfect fit for the culture we're building."
Brentford's director of football, Phil Giles, reflected fondly on Mbeumo's tenure. "Bryan came to us as a teenager, and it's been a pleasure to watch him develop," Giles said.
"Our fans have loved him, and he's been part of our greatest days. This is the right time for him to move to one of the world's biggest clubs, and we're happy for him."
Recent updates on X from Manchester United's official account confirmed Mbeumo's inclusion in their pre-season tour squad for the United States, which departs on July 22.
A post from @ManUtd read: "Welcome to the family, Bryan Mbeumo! Excited to see #19 shine on tour! #MUFC." Amorim also shared enthusiasm, posting: "Bryan's energy and hunger will lift us. Let's get to work! #United."
Mbeumo's arrival signals United's intent to compete at the highest level, with fans eagerly awaiting his debut in the iconic red shirt.