Ack Ack was an American Thoroughbred Hall of Fame racehorse. He raced with success at age two to four, scoring wins in the important 1969 Withers Stakes and Arlington Classic. In 1971 at age five, Ack Ack blossomed into the year's most dominant horse. Conditioned by Charlie Whittingham, Ack Ack won seven straight graded stakes races on both dirt and grass courses at a variety of distances. His performances earned him United States Horse of the Year honors.
Owned by Harry F. Guggenheim's Cain Hoy Stable, Ack Ack was sold by the executors of his estate following Guggenheim's death in January 1971. New owner, E. E. "Buddy" Fogelson, husband of actress Greer Garson, retired the horse at the end of his most successful year to stand at stud at Claiborne Farm near Paris, Kentucky where he sired 40 stakes winners, including champion sire Broad Brush and Youth, the 1976 American Champion Male Turf Horse who won a combined four Grade/Group 1 races in France, Canada, and the United States.
In 1999, The Blood Horse, Inc. selected Ack Ack as one of the top 100 racehorses of the twentieth century.