Glasberg's production company is called When Pigs Fly Incorporated.
Glasberg started out writing for animated shows such as Rugrats, Power Rangers, Duckman and Aaahh!!! Real Monsters. Glasberg's credits include Crossing Jordan, The $treet, The Evidence, Bones, Shark and The Mentalist. At the time of his death, he was the showrunner for NCIS. His death made the writing duo of Frank Cardea and George Schenck the new showrunners of NCIS.
Sometime after Glasberg earned the title of showrunner for NCIS, he stated that he was a big fan of the M*A*S*H series, and his inspirations from M*A*S*H are occasionally visible within NCIS episodes. For example, the Season 8 episode A Man Walks into a Bar was inspired by the M*A*S*H episode Dear Sigmund, and the character of Dr. Cyril Taft (Jon Cryer) was inspired by Alan Alda's Hawkeye Pierce. Glasberg also adapted a M*A*S*H tradition in which episodes are formatted as letters from a main character to a loved one. The Season 12 episode House Rules was very reminiscent of the M*A*S*H* episode Dear Dad, and the Season 13 episode Deja Vu was reminiscent of Dear Sigmund.