Tommy, along with his sister Tammy, live miserable lives due to their constantly busy father and mother who is never around, and their evil babysitter robot, who usually tortures them with many weapons. Luckily, like their father, they also have Cosmo and Wanda as their fairy godparents to make them happy and grant them wishes.
He wears pink clothing and a pink hat, similar to what his father once wore as a kid, although Tommy's hat is a different design which slightly resembles a crown. Other than the color of his hair, which is black, and his nose, which is pointy instead of round, Tommy is almost completely physically identical to the ten year old Timmy. He also has buck teeth, getting them possibly the same way Timmy did.
Not much else is known about him, as he has no speaking lines (by himself) and is only seen briefly at the end of Channel Chasers, digging up a time capsule with his sister that his father buried twenty years ago. When he learned that he was going to be babysat by robot Vicky, he tried to cling to his father's legs while pleading him not to leave, but Timmy shook him off and said goodbye to him and his sister, which is when their names were heard.
Tommy nor his sister are ever brought up in the show again. However, the Fairly Odd Movie's official website has a reference to Tammy and Tommy in its character quiz. One of the questions asks what you would name your children, and one of the answers is "Tammy or Tommy", selecting just this answer matches you with the character Tootie.
When Timmy's children were first shown, it was unknown who their mother was, and this was intended by the creators who gave Tammy and Tommy features of Timmy and both of his love interests, Tootie and Trixie Tang (the latter of whom did not appear in Channel Chasers). After the release of "Grow Up, Timmy Turner!" however, it is heavily implied that Timmy falls in love with Tootie in adulthood, although it is still unkown who is Timmy's wife Likewise, the official Nickelodeon website for the FOP movie contains a quiz which indicates that Tootie named the kids.
Interestingly, it is never stated whether or not Cosmo and Wanda are actually Tammy and Tommy's godparents, and the Fairly Odd Movie leaves open the possibility they could still be Timmy's.
It is also possible Timmy shared the secret of the fairy god parents with his children, feigned forgetting them, or eventually did willingly give them up some period after the live action movies take place. The latter option could also explain why Cosmo and Wanda were given Tammy and Tommy as godchildren as opposed to being assigned another kid immediately after leaving Timmy.
The name "Tommy" has also been used by several characters to mistakenly call Timmy. It was also the name of his wished-for older brother. Both Tommy and Tammy have names similar to Timmy to keep the mother's identity further hidden.