LAPD officers responded to a death investigation on the 2800 block of Bright Lane around 8:15 p.m.
The victim's daughter arrived at the home and found 78-year-old Joseph Gatto suffering from a gunshot wound.
Responding officers say Joseph's body was slumped over on a chair. His body was removed from his Silverlake home around 10 a.m. Thursday.
Investigators say the house had been ransacked. No arrests have been made.
The case is being treated as a possible home invasion murder.
Immediately after the discovery, detectives started canvassing the neighborhood. On Thursday, they stopped trash pick-up on Bright Lane as they searched for evidence.
"They are going to go door-to-door to determine what people may have seen, what they may have heard, so that detectives have that information in furtherance of their efforts to solve the case," said Dep. Chief Kirk Albanese of the Los Angeles Police Department.
Mike Gatto's spokesman, Justin Hager, says Joseph was a longtime Los Angeles Unified School District art teacher and had become a well-known jewelry craftsman following his retirement. Hager said the Assemblyman learned of his father's death by phone in Sacramento.
"It's both shocking and very hard for the family. It's hard for this community. I think a lot of people are still in a state of disbelief, including me," Mike Gatto told reporters.
There is no indication Mike Gatto's political career played any role in his father's murder, police say.
His 78-year-old father founded the Visual Arts Department of Los Angeles County High School for the Arts and had reportedly worked for LAUSD for over 40 years. Joseph was honored at the White House with the National Distinguished Teacher Award three times throughout his lifetime.
Those mourning Joseph's death include singer Josh Groban, who took to Twitter to pay his respects to the fallen art teacher.
"LACHSA lost one of their legends last night in a senseless act of violence. RIP Joseph Gatto, visual arts department founder and great guy," tweeted Groban.
Los Angeles Mayor Eric Garcetti released the following statement Thursday: "My thoughts and prayers are with the Gatto family. This tragedy is devastating to them and is of concern to the entire community. I've spoken with Chief Beck and the LAPD is conducting an aggressive investigation."
Democratic Assemblyman Mike Gatto of Los Angeles was elected to represent California's 43rd District in a special election three years ago.
His father lived in Silver Lake alone, but friends say he was a man of faith who will be missed.
"When you have someone come into church everyday, you have someone who has a focus in life and sees beyond the present realities," said Rev. James Mott of Our Mother of Good Counsel Church.
Congressman Brad Sherman (D-Sherman Oaks) released a statement Thursday to express his condolences.
"I came to know Joseph Gatto through his son Mike, one of my closest friends. He was thoughtful, gracious, and so proud of his son Michael," Sherman said. "My heart goes out to Mike and his sisters Nicole and Mariann."
LAPD says Joseph's death is the first murder in the Silver Lake neighborhood of Los Angeles this year.