Since 1988, Kosman has been a music critic of the San Francisco Chronicle.[1] He was hand-picked in 1993 by the music critic Robert Commanday to succeed him as chief classical music critic for the Chronicle.[2] He frequently writes on contemporary classical music, promoting composers such as John Adams, Aaron Jay Kernis, Michael Gordon, Chen Yi, and Lisa Bielawa. Other topics Kosman engages with include "orchestral management" and the pianist David Helfgott, who came into the spotlight after the movie 1996 Shine.[1] The music critic Jayson Greene described Kosman as having a "congenial, probing tone that blends a reporter’s instincts with a critic’s acumen."[1] Kosman retired from the Chronicle in late April 2024;[3] writer Andrew Gilbert described him as "an essential component of the Bay Area’s arts ecosystem, providing pithy and cogent criticism and a form of institutional memory that can’t be replaced."[4] According to Kosman, “It’s been made pretty clear that there won’t be somebody hired who will [replace me as the new] classical music critic."[4]