Sam Speed is Chris Thorndyke's maternal uncle and the leader of the Speed Team, a special unit of the Station Square police force that uses high-performance Formula racing cars. His rivalry with Sonic is a recurring theme throughout Sonic X's first two seasons. Sam Speed is 28 years old, 183 cm (6ft) tall, weighs 80 kg (176lb), and he is voiced by Souichirou Tanaka in Japan and Frank Frankson in the US.
A running gag in the original Japanese version of the show involves Sam having a different nickname in each of his appearances, some examples being "Highway Star" and "Love Express". In the English version, his only nickname was "Speed King".