Kerwin grew up in the Chicago suburb of Flossmoor, Illinois. After graduating from USC's Film School in 1972, he moved to New York City to pursue acting on the stage. After several off-off Broadway productions, he was cast for a brief stint on "The Young and the Restless" in Los Angeles. He ended up staying in LA for the next 15 years, working steadily in films, TV and on stage.He worked regularly in TV, from standard network fare to recurring roles in "Roseanne", "The West Wing", "Nip/Tuck", and more. He appeared in numerous TV movies and miniseries and starred in Showtime's critically acclaimed series, "Beggars & Choosers".In feature films Kerwin landed the role of Sally Field's errant ex in "Murphy's Romance", and he played Harvey Fierstein's love interest in the groundbreaking film, "Torch Song Trilogy" (a role he also played in the Tony Award winning play). he worked opposite Robin Williams in "Jack", Michelle Pfeiffer in "Love Field", and Sissy Spacek in "Hard Promises". He played Katherine Heigl's father in "27 Dresses" and Emma Stone's father in "The Help".The focus of Kerwin's work has always been the stage. He has performed in regional theatres throughout the country, including South Coast Rep, San Diego's Old Globe, The Seattle Rep and The Mark Taper Forum in Los Angeles. He and his wife, Jeanne, a theatrical producer, moved to Manhattan's Upper West Side in 1993, where they raised their three children. While there, he worked extensively both on and off Broadway, culminating with his 19 month run in Tracy Lett's Tony and Pulizer Award winning play, "August: Osage County".Widowed in 2016, Kerwin resides in NYC.