Knight was born in Princeton, New Jersey. He was educated at The Thacher School in Ojai, California, and attended Wesleyan University, graduating in 1980, a year ahead of schedule.

Knight and Hickland were honored for their charitable work by the West End Intergenerational Residence in Manhattan in 1999.

Knight was honored with two Daytime Emmy Awards for ‘Outstanding Younger Leading Actor’ (1986 and 1987). In 2001, he was honored with his third Daytime Emmy Award. He also received the 1997 Soap Opera Digest Award for ‘Best Supporting Actor’ and a nomination in the same category in 1998. In 2005, he was nominated for an Emmy for ‘Outstanding Leading Actor’.

Knight’s first major acting role was portraying Tad Martin on the soap opera All My Children. His first stint on the show ran from 1982–1986. He returned from 1988–1990, and again from 1992 until the ABC series finale in 2011 and the online revival of the series in 2013. Knight also appeared as Ted Orsini on AMC from 1993–1994.

In 2015 and 2016, Knight had a recurring role as Dr. Simon Neville on CBS’ The Young and the Restless.

On February 2, 2017, Knight made a surprise appearance on the Hallmark Channel’s Home & Family show, where he was reunited with a number of his former All My Children castmates.

On September 30, 2019, Knight began appearing in a recurring role on General Hospital as lawyer Martin Gray.