On SpongeBob, he has provided the voice of Sheldon J. Plankton, Larry the Lobster, Fred, and various recurring characters since the show's debut in 1999.

He served as a layout assistant on the second season of The Ren & Stimpy Show and endured harsh working conditions under John Kricfalusi.

He followed future showrunner Bob Camp and others to Games Animation, where he completed the rest of his work and switched to Joe Murray's unit.

He became a major crew member on Rocko's Modern Life, voicing Filburt while directing and writing multiple episodes, a contrast to his minor role at the perpetually suffering Ren & Stimpy unit.

Lawrence also worked as a producer on the television series Johnny Talk and as a writer on Rocko's Modern Life, The Twisted Whiskers Show and Mighty Magiswords.