Geary was originally hired for a 13-week in General Hospital, which grew into a full contract role. Geary received Daytime Emmy nominations for Outstanding Lead Actor in a Drama Series in 1980, 1981, and had his first win in 1982. Geary was nominated again in 1983, before leaving the show in 1984.
In 1991, Geary returned to General Hospital as Luke's cousin and look-alike Bill Eckert, due to the actor's desire to play something other than Luke. However, due to audience feedback and demand, the character was killed off and Geary resumed the role of Luke in 1993. Geary was nominated in 1997 and 1998 for Daytime Emmys for Outstanding Lead Actor, and had his second win in 1999, and his third in 2000. He received another nomination in 2003, and had his fourth win in 2004. When Geary won for the fifth time in 2006, he set the record for most lead actor wins. Geary received another Emmy nomination in 2007, and in 2008, he again set a record for most lead actor wins with his sixth Emmy for Outstanding Lead Actor. Having received his last nomination in 2009, Geary again set a record in 2012 with his seventh win for Outstanding Leading Actor in a Drama Series.
A notable exception from his series of dramatic roles is the part of a scientist/studio engineer in the comedy/spoof movie UHF. He also starred in 1987's Disorderlies with rappersThe Fat Boys.
In 1994, he appeared in an episode of Roseanne, alongside his co-star Genie Francis.