Tom Horton is born in 1910 and married his wife Alice Grayson on March 7, 1930. Tom is a prominent doctor at Salem University Hospital and has five children, Tommy, Addie, Mickey, Bill, and Marie. In 1968, Tom learns that Mickey is infertile, and when Tom confronts Mickey's wife, Laura Horton, about her pregnancy, she tells Tom that Bill had raped her. The two agreed to keep their secrets from Mickey in order to spare his feelings. In 1974, Tom is devastated when Addie is run over shortly after giving birth to Hope Williams.

In 1977, Tom has a heart attack and remains in the hospital for several months. In 1978, Tom is promoted to Chief of Staff at University Hospital. Tom reads poetry, which he wrote himself, under the name Norm De Plume, wearing a disguise so Alice wouldn't know what he was up to. When it is discovered their first marriage was invalid they marry again on October 17, 1989. In 1993, Alice and Tom set up and found the Horton Center, which runs out of their home and provides shelter and help to run-away teens or families in need. Tom last appears on February 9, 1994 due to Carey's failing health. Following Carey's death in March 1994, the character of Tom dies off screen on June 21, 1994.

In 2024, Tom appears in flashbacks as the family remanences on the good times while salvaging through the charred remains of the Horton house. In further flashbacks, he is played by Zach Chyz where Tom and Alice are young and struggle until they buy the house for them and their children.

For his role as Tom, Carey won the Outstanding Actor in a Daytime Drama Series Award at the 1st Daytime Emmy Awards in 1974.^[2] In 2020, Charlie Mason from Soaps She Knows placed Tom as #7 on a list of the 35 most memorable characters from Days of Our Lives, commenting that "Only the hourglass itself could possibly be a bigger part of the DNA of Days of Our Lives than the much-missed MacDonald Carey’s family man, a steadying presence in a town that desperately needed it".^[3]