Born in Mountain View, California, Tommy Sondgroth fell in love with horses after his father bought a roping horse from actor Slim Pickens. One day while at a branding with his father, they ran into NRCHA Hall of Fame inductee Tony Amaral, who suggested he take Tommy and make a cowboy out of him.

Tommy learned all he could and showed his first horse for money when he was 13. Two years later, he showed his first bridle horse at the Cow Palace in the Open division. He made the Open Finals at the Cow Palace when he was 18.

Tommy was also successful as a roper in the Rodeo Cowboys Association (now the PRCA) but then decided to focus on becoming a trainer.

As a dedicated family man, Tommy decided to spend more time at home than traveling to horse shows. He used his knowledge to continue training from his home in California.