In 1937 with Albany he raised his average to .242 and joined Union Springs of the Alabama-Florida League in 1938. In 1939, Gremp switched to first base playing with Hamilton of the PONY League. He joined York of the Class B Inter-State League in 1940 and hit 15 home runs with 81 RBIs while batting .293, earning a September call-up by the Boston Braves. In four games Gremp got two hits in nine at-bats at the major league level.

He remained with the Braves in 1941 as a back-up first baseman and batted .240 in 37 games. In 1942, he played 72 games and batted .217. That year, he and Johnny Sain, Johnny Pesky, Ted Williams and Joe Coleman were sent to Amherst College for naval training. In May 1943, the training mates and others played as a team against Harvard University.

Later in 1943, Cadet Gremp was at Chapel Hill, North Carolina, then Whiting Field at Pensacola NATB in 1944, and USNAAS Saufley Field, Florida in 1945. He played baseball with service teams throughout these years.

Gremp returned to the Braves organization in 1946 and was assigned to Hartford of the Eastern League where the 26-year-old batted .281. It was to be his last season in organized baseball.

Buddy Gremp passed away on January 30, 1995 in Modesto, California.