The early years were precarious. UMBC opened in 1966 as a commuter campus with no clear mission beyond absorbing overflow from the College Park flagship. Its first chancellor, Albin Owings Kuhn, was an administrator from College Park who arrived without political backing. The 1960s civil rights movement and the Vietnam War were already reshaping every American campus. UMBC, founded as the first public Maryland university to admit students of all races from day one, became a quiet test case for what an integrated state university could look like. Kuhn resigned in 1971. Calvin B. T. Lee took over. John Dorsey, an administrative vice president at College Park, became the third chancellor in 1976. The university struggled to define itself against the much older, much more politically entrenched College Park campus, and against the professional schools at the University of Maryland, Baltimore in downtown Baltimore. The county in its name was, in the words of the historians who later studied the period, an afterthought.

Freeman A. Hrabowski III became president in May 1992 and stayed for thirty years. Hrabowski, who had been arrested at age twelve during a 1963 civil rights march in his hometown of Birmingham, came to UMBC with a specific theory of the case: a public university could become world-class in scientific research by becoming the best place in the country for African American and other underrepresented students to study STEM disciplines. The Meyerhoff Scholars Program, established in 1988 before Hrabowski arrived but expanded enormously under his leadership, became the institutional engine of that ambition. Meyerhoff scholars receive full scholarships, mentoring, summer research placements, and structured peer-group support through their undergraduate years. The program's outcomes are studied by other universities trying to figure out how to replicate them. UMBC became and remains a top producer of Black students who go on to earn PhDs and MD-PhDs in the sciences. Time named Hrabowski one of the 100 most influential people in the world.

On March 16, 2018, in the first round of the NCAA men's basketball tournament, the UMBC Retrievers - a 16 seed in the East region - beat the University of Virginia, the 1 seed and overall top seed in the tournament. The final was 74-54. It was the first time in 136 attempts since the tournament's bracket-seeding system was introduced in 1985 that a 16 seed had ever beaten a 1 seed. The game became one of the most widely-watched upsets in NCAA history. The Retriever - a dog associated with no obvious athletic ferocity - became, briefly, the most famous mascot in college sports. The team lost in the second round to Kansas State two days later. The Cavaliers of Virginia, humiliated, regrouped and won the entire tournament the following year. UMBC returned to the tournament in 2026 for the first time since, losing to Howard in the First Four. The win remains a singular event in NCAA history and an unlikely highlight reel for an institution most national fans had never previously heard of.

UMBC's research portfolio focuses on areas where its location and partnerships have given it specific advantages. Three Joint Centers operate in collaboration with NASA Goddard Space Flight Center, twelve miles east in Greenbelt - the Joint Center for Earth Systems Technology, the Goddard Planetary Heliophysics Institute, and the Center for Space Sciences and Technology. The Center for Accelerated Real-Time Analytics focuses on data science. The bwtech@UMBC research and technology park houses more than 130 companies and three incubators in cybersecurity, life sciences, and clean technology. UMBC researchers have received forty NSF CAREER awards since 1995 - nine of those since 2017 - and two Presidential Early Career Awards in Science and Engineering, one from the NSF in 2005 and one from the NSA in 2014. The university is one of two public Maryland institutions with a Howard Hughes Medical Institute investigator on faculty.

UMBC's 500-acre campus sits in southern Catonsville, three miles outside the Baltimore city limits but using a Baltimore mailing address - the university successfully lobbied for that designation in its early years to compensate for the inconvenient county name. Academic Row runs through the heart of the central campus, a tree-lined pedestrian concourse that connects the original buildings to the more recent Performing Arts and Humanities Building, which opened in two phases between 2012 and 2014. The Albin O. Kuhn Library and Gallery anchors the northern end. The Commons, the student union, anchors the southern end. The campus has the distinct fingerprint of an institution that built itself out of necessity rather than from a master plan - the architecture is a survey of postwar modernist styles, with later buildings layered on top in 21st-century glass and brick. Valerie Sheares Ashby became the university's first female president on August 1, 2022, succeeding Hrabowski. She inherits an institution that figured out what it was, in part, by refusing to pretend it was anything it wasn't.