Ullman was born in Eilat, Israel, to American parents Laura (née Ehrenkranz) and Brian Ullman. His maternal grandfather, Joseph Ehrenkranz, is an Orthodox Rabbi in Stamford, Connecticut, and Ullman was raised in Conservative and Orthodox Judaism. His family is related to Connecticut Senator Joe Lieberman. After his first birthday, his family moved to Fairfield, Connecticut, in the United States. When Ullman was younger, his father worked as a clown.[citation needed] He attended camp the following summer and landed the role of Peter Pan (both lead and supporting roles), which helped him discover his talents in acting, singing, dancing, and reading drama novels.

Ullman speaks fluent Hebrew and taught himself how to play the drums. He is a graduate of Fairfield Warde High School. He lives in Southern California with his friends, two of them being Lisa and Jess Origlasso from the pop band the Veronicas.[citation needed]

Ullman's first professional role was as Louis in the national touring company of The King and I along with Jesse McCartney. Other productions he worked on include Peter Pan at the Polka Dot Playhouse, The Music Man with the New England Repertory Company, and Just People at the Long Wharf Theatre. He received a 1998–1999 Best Actor nomination from the Connecticut Critics' Awards for his character Stanley in Stamford Theater Work's A Rosen by Any Other Name. He graduated from the HOBY program of Connecticut in March 2003.

Ullman is best known for his starring role as Phil Diffy, a teen from the year 2121 on Disney Channel's Phil of the Future, a series that debuted June 2004. He also starred as Roscoe in Disney's made-for-television film Pixel Perfect and as Sam in ABC Family's television film Searching for David's Heart (2005). Ullman was an identified member of the Disney Channel Circle of Stars, and appeared with other members of the Circle in the music video for "A Dream is a Wish Your Heart Makes," where he sang as well as played the drums. Ullman also appeared in the Law & Order: SVU episode "Obscene," in which his character rapes a teen star (Maggie Grace).

While Ullman previously went by the stage name Ricky, he started using his real name in 2006 when he guest-starred on an episode of House and continues to use Raviv on all projects since. In 2008, he appeared in an episode of the television series The Middleman.

He is currently playing the character named Kip in a new show called Rita Rocks on Lifetime. He is Rita's daughter's boyfriend, who also plays the drums in Rita's band. The show has been picked up for another full second season, 20-episode order.

In June 2006, Ullman and a few of his friends created a parody hip-hop music video, "Pointy Hat (The Boat Song)," under the name the Webee Boys. The video was viewed over 300,000 times since it was posted to YouTube on June 26, 2006. Two other music videos were released, "Refrigerator (Gangsta' Way)" in August 2006, which was viewed over 90,000 times and "Bop It (Webee Anthem)" in March 2007. The Webee Boys have performed live exclusively at the Gig in Hollywood, California.

In December 2006, Ullman met actor Douglas Smith of Big Love fame and together they formed a band called Goodbye Ian. The group expanded to as many as seven people and later changed its name to His Orchestra. Ullman plays drums and glockenspiel in the band, which released its debut album, Field Guide to the Wilds, on February 24, 2009.

Both groups communicate online through the social networking Web sites MySpace and Twitter.