During an illustrious career in which she was frequently ridden by the great Hall of Fame jockey, Earl Sande, Milkmaid won races at both sprint and longer distances. At age three and four her success against other fillies and mares resulted in her being saddled with high weight for most of her career. On April 21, 1919, Milkmaid won the Wilmington Purse at Havre de Grace Racetrack, defeating a field of colts with Kentucky Derby and Preakness Stakes aspirations in a time that was just one-fifth of a second off the track record. In May, Milkmaid and her Kentucky Derby-winning stablemate Sir Barton were entered in the Preakness Stakes. Milkmaid finished eighth but according to a June 27, 1994 Sports Illustrated article, jockey Earl Sande was "told to veer Milkmaid in at the start, break up the alignment of the field and allow Sir Barton time to get a good position." Sir Barton proved he didn't need Milkmaid's help to win the Preakness and went on to capture that year's U.S. Triple Crown. However, on an equal footing as demonstrated in the Wilmington Purse, Milkmaid had great success against colts including a win in the 1919 Kenner Stakes at Saratoga Race Course in which she beat Sam Hildreth's top colt, Cirrus. Burdened with fourteen more pounds than Harry Payne Whitney's winning filly Vexatious, Milkmaid ran second in the 1919 Alabama Stakes at Saratoga. Milkmaid's 1919 performances resulted in her being voted American Champion Three-Year-Old Filly
1920 racing season
On August 19, 1920, racing against males, four-year-old Milkmaid set a new Saratoga Race Course track record for seven furlongs. A few weeks later on September 3, she set another track record against males in winning the Great Neck Handicap at a distance of a mile and a sixteenth at Belmont Park. For 1920, Milkmaid earned American Champion Older Female Horse honors.
Retired to broodmare duty at her owner's Yarrow Brae Stud farm in Maryland, Milkmaid produced two foals from J.K. L. Ross's stallion, Cudgel. Her colt, Lactarius, was born in 1924 and raced for J.K. L. Ross, notably winning the Connaught Cup Stakes. Financial problems resulted in J.K.L. Ross liquidating his racing stable and in August 1926 Milkmaid was sold at a Saratoga auction. Her second foal was born to her new owners in 1927. Named Milkman, the colt had modest success racing but as a sire did produce a number of successful runners.
