Lawrence K. Grossman, who expanded public television programming as the top executive at PBS in the 1970s and 1980s, and who later led a resurgence of NBC’s news division before budget battles with the network’s corporate bosses forced his departure, died March 23 at his home in Westport, Conn. He was 86. As a longtime advertising executive, Mr. Grossman was an unlikely choice to lead the ad-free Public Broadcasting System. But one of his advertising agency’s clients in the 1970s had been PBS — his company designed the network’s familiar logo featuring the letter P combined with the stylized profile of a head — and he had previously worked at CBS and NBC. Mr. Grossman moved to Washington in 1976 to take charge of PBS, at the time little more than a loosely aligned group of hundreds of locally controlled educational TV stations around the country. During his eight-year tenure, he maintained financial stability while giving PBS more of a national presence, largely through cultural programming and news. In 1984, despite having no experience in daily journalism, Mr. Grossman became the head of NBC News, personally chosen by network chief Grant Tinker. Mr. Grossman was dismissed in 1988 and replaced by Michael Gartner. Lawrence Kugelmass was born June 21, 1931, in Brooklyn. After his father died, he was adopted by his mother’s second husband, Nathan Grossman. He graduated from Columbia University in 1952 and spent one year at Harvard Law School before going to work in the promotions department of Look magazine. He joined the advertising department at CBS in 1956, then moved to NBC in 1962, becoming the network’s vice president of advertising. He ran his own advertising agency from 1966 to 1976. After leaving NBC, Mr. Grossman taught at Harvard’s John F. Kennedy School of Government and, in 1993, became president of Horizons TV, a onetime challenger to PBS and C-SPAN. In the late 1990s, he and former PBS chairman Newton Minow launched Digital Promise, a nonprofit organization that receives federal and private funding to use digital technologies to improve education. Survivors include his wife of 64 years, the former Alberta Nevler of Westport; three daughters, Susan Grossman of Brooklyn, Caroline Grossman of Waltham, Mass., and Jennifer Grossman Peltz of Manhattan; a brother; six grandchildren; and two great-granddaughters.