Bloom was born in Merrick, New York, the brother of producer-actor Scott Bloom and musician Mike Bloom. Bloom had an early interest in acting, including appearing in several commercials as a child, but made his big break in the Sergio Leone film Once Upon a Time in America. From there, he was offered the role of Dusty Donovan in the hit soap opera As the World Turns, which he played for several years. During that run, Bloom became the youngest winner of a Daytime Emmy Award in the category of Outstanding Young Leading Man during the 12th Daytime Emmy Awards show for his performance on the series. Despite his success, he soon grew tired of the scheduling involved in that field and eventually left the series to star in several television movies and myriad guest appearances.

After leaving the soap opera, Bloom starred in several made-for-television films with teen subjects, including Crash Course (1988), Dance 'til Dawn (1988) and Desperate for Love (1989). This opened his appeal to later roles, which would include spots in Melrose Place, 2000 Malibu Road, CSI: Miami, Law & Order: Special Victims Unit, Drive and HBO's Oz. He played the role of fanatical cult leader Jonas Sparrow in the Joss Whedon show Dollhouse. Bloom also starred in a series of 1994 television movies playing Bandit, a part loosely based on the iconic Burt Reynolds role. Bloom continues his working relationship with Carnahan, playing private mercenary bad guy "Pike" in the 2010 movie The A-Team, which Bloom also co-wrote with Carnahan, who directed the 20th Century Fox feature based on the popular television series.

Bloom is expanding his resume to include voice work, both acting in animated projects and video games as well as commercial voiceovers. His recent work has been a series of commercials for the 2009 Cadillac Escalade Hybrid, directed by filmmaker Joe Carnahan, the voice of Alex Shepherd in Silent Hill: Homecoming, Kane in Kane & Lynch: Dead Men and its sequel, Kane & Lynch 2: Dog Days, and the voice of Jackie Estacado in The Darkness II. He voiced Captain America in the animated show The Avengers: Earth's Mightiest Heroes and the video games Marvel vs. Capcom 3: Fate of Two Worlds, Ultimate Marvel vs. Capcom 3 and Marvel Heroes. He voiced William "B.J." Blazkowicz in Wolfenstein: The New Order and Wolfenstein: The Old Blood. He has also voiced a number of characters for BioWare video games, most notably the dwarf storyteller Varric Tethras in Dragon Age II (2011) and its sequel Dragon Age: Inquisition (2014).

His hobbies include writing, cooking, and designing and building furniture. He owns and runs an online store called Animal World Network. Bloom practices a rare martial art known as bojuka.