In 1984, when Grant was a graduate student, he received a role of Rick Hyde in a soap opera Ryan's Hope and stayed in it till 1987. In 1987 he was nominated for Daytime Emmy as "Outstanding Young Man in a Daytime Drama Series". After leaving Ryan's Hope he decided to study acting mastery in the London Academy of Music and Dramatic Arts. After couple years of studying, Show returned to New York and after several ordinary roles, he got an invitation to play in Beverly Hills, 90210. This role boosted his career and then he got the same role in the second series of Beverly Hills, 90210, popular soap opera Melrose Place where he continued to play his character Jake Hanson.

This show brought him love of viewers, and made him one of the most popular actors on TV. Despite so busy schedule of shooting in Melrose Place, Grant Show always found time for other projects on TV: Burke's Law, Texas, Between Love and Honor, Pretty Poison, Mother Knows Best. His character Jake Hanson appeared in Models Inc. (1994) and Saturday Night Live (1995) and remained as his best and well-known role.

But his career didn't stop at this point. After he made a name for himself in Melrose Place he starred in a vast number of TV series, including show Beautiful People on ABC (2005 – 2006), Point Pleasant (2005 – 2006), Swingtown (2008), Private Practice (2008 – 2011) and other. In 2007 he played gay character Jack Dawson in three episodes of FX show Dirt. Since 2013 up to date he has starred in comedy-drama series Devious Maids on ABC where he has played rich Beverly Hills socialites Spence Westmore. This role brought Grant Show his biggest income in his career (5.5 million dollars) and made his net worth 67 million dollars in total.

Apart from work on television, Grant Show also played at The Alley Theatre in Houston. It wasn’t his regular income source but he enjoyed it a lot. He played Terry Malloy in On The Waterfront, The Glass Menagerie and some other plays.

Despite his public life, there is not much information in his biography about his private life. He met his first wife in 2003 when they both posed for women's clothing store Lane Bryant.  It was Scottish model Pollyanna McIntosh After one year of dating, they married. But their marriage has lasted only to 2011. Than in July 2012 Show made a proposal to American actress, ballet dancer and choreographer Katherine LaNasa. Their wedding was on August 18, 2012 and up to date they are in a happy marriage.