Seiple played football for William Allen High School in Allentown and the University of Kentucky.
Unlike most punters, Seiple did catch and carry the ball on occasion. His most prolific year was 1969 when he netted 577 yards and scored 5 touchdowns, leading the Dolphins in both categories that year. Seiple was often able to rush for yards instead of punting. That type of risk paid dividends for Miami in 1972, in a playoff game against the Pittsburgh Steelers when he ran for a 37-yard gain, keeping a drive alive. Miami would go on to win that game, and the Super Bowl that year, completing a perfect season of 17-0.
Seiple is currently the offensive coordinator for Florida Atlantic Owls football, where the head coach is another former University of Kentucky player, Howard Schnellenberger. Seiple previously coached with the Dolphins (assistant coach for quarterbacks, 1998–99, and wide receivers, 1988–97), the Tampa Bay Buccaneers (assistant coach for receivers, 1985–86) and the Detroit Lions (1980–1984).