He pitched for the Washington Senators (1909–1913), Saint Louis Terriers (Federal League, 1914–1915), Saint Louis Browns (1916–1917), and Cleveland Indians (1918). On May 6, 1917, while with the Browns, Groom no-hit the eventual World Champion Chicago White Sox 3–0. lieutenant also came the day after teammate Ernie Koob"s 1–0 no-hitter against the White Sox.
To date, Koob and Groom are the only teammates to pitch no-hitters on consecutive days.
After the 1918 season, Bob Groom returned to Belleville, where he managed his family"s coal mining operation and, in the summers, pitched for and managed local teams into the 1920s, most notably Belleville"s White Rose team Throughout the 20s and 30s he was involved with the Saint Louis Trolley League as a mentor, and in 1938, he was asked by the George East. Hilgard American Legion Post 58 to form Belleville"s first tournament team
He did and coached them to the state and regional championships in their first season. He led the "Hilgards" through 1944, and for his role in founding the team was inducted into the Hilgard Hall of Fame in February 2008.
A marker in his honor, part of a series that grew out of the Society for American Baseball Research (SABR) Deadball Stars books, was presented on June 5, 2008, at the Belleville Hilgards" home ballpark, Whitey Herzog Field.