The San Bernardino County Registrar of Voters last week reported that Cruz received 12,273 votes during the Nov. 6 election enough to capture a seat on the board.
The librarian at Pinacate Middle School in Perris finished just ahead of incumbent Fred Youngblood, who finished fourth with 12,146 votes.
Cruz said his profession likely helped him get elected.
"Being a teacher, I think that's what made people vote for me. Like, `Hey maybe this guy can relate to us,"' said Cruz, 43, of Chino.
"The way I perceive teachers is they're just like our children. They're middle-class kids that became teachers, and I think most teachers are like American and apple pie. They're ordinary folks."
Incumbent James Na led the 11-person field with 20,373 votes. Newcomer Irene Hernandez-Blair finished second with 14,781 votes.
The top three vote-getters were elected to the board.
Unofficial results after Election Day had Youngblood in third. Cruz said that the report resulted in him believing Youngblood had secured his seat and the election had been finalized.
"I just thought, the day of election - it's done. And I thought, maybe in two years from now, I'll do a little better," Cruz said.
"I was a bit discouraged, too. Discouraged that maybe I could have done something different, maybe I didn't sell myself."
However, the numbers changed when the Registrar of Voters started counting provisional or late mail-in ballots.
"Maybe he had a campaign that we didn't know about. But I tend to think that it was because the people who were handed those ballots didn't have an understanding of who they were voting for. And his name was first part of the ballot and voted for him. That is my impression," said Youngblood, who was elected in 2004 to the Chino Valley Unified school board.
Cruz admits he didn't do much campaigning, and raised just $200 to put up 30 signs in the district, which includes schools in Chino, Chino Hills and Ontario.
The Committee to Re-Elect Fred Youngblood for School Board 2012 spent more than $5,000, according to campaign statements from July 1 through Sept. 30.
"In my personal opinion, people who don't know anything about me probably voted me in the mail-in ballots," Cruz said.
"In my community, people were aware of what I was doing ... I'm being frank with you, I think it has to do with being a teacher."
Youngblood said he had consistently been ahead by 1 to 2 percentage points during early counting.
"And that was kind of strange, because some people work very hard for the results they got and he didn't put in that much effort ...," Youngblood said about Cruz.
"Hopefully, the level of effort to get elected is not a reflection of a desire to serve, and I don't think it is."
Youngblood said he doesn't plan to seek re-election.
"I serve for the voters and when they say no longer, then it is no longer ... " he said.
"My prayer is that the board will continue to be functioning well."
Cruz said the last school board meeting he attended was a year and a half ago.
He will take the oath-of-office on Thursday.
Board members will meet at 7 p.m. at the Chino Valley Unified offices, 5130 Riverside Drive, Chino.
Reach Canan via email, call her at 909-987-6397 ext. 425, or find her on Twitter @ChinoValleyNow.