But his tenacity has also earned respect. His opposition to fracking in their La Habra Heights neighborhood attracted notice from an activist who urged him to run for City Council in 2014. He lost.
Greg Stefflre, who served on the La Habra Heights planning commission with Villanueva, said his colleague was passionate in denouncing plans to activate oil wells in the community.
"His posture at the podium was a bit pugnacious and as the significance of his comments grew he leaned forward and thrust his jaw out. Made quite an impression," said Stefflre, who disagreed with Villanueva but said he found him to be thoughtful and respectful.
Villanueva has always gravitated toward athletic events linked to the department, finding himself less keen on making drinking buddies with other deputies, said Vivian, who with her husband is a part owner of a CrossFit gym in Whittier. He tends to keep a small circle of friends, she said.
One of them, retired Capt. Matt Rodriguez, said that when the two worked together as drill instructors at the Sheriff's Academy in the late 1990s, Villanueva -- nicknamed "the scientist" -- often spoke freely about his long-term goal: to become sheriff of Los Angeles County.
When their union, the Association for Los Angeles Deputy Sheriffs, endorsed Block's 1998 re-election bid despite three-quarters of deputies advocating for someone new, Rodriguez said he and Villanueva went to the union's leaders, questioning the decision and, eventually, the organization's finances.
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ALADS moved to suspend both men, who started a separate guild, the Los Angeles Sheriff's Professional Association, which still exists today. The two men also worked to get ALADS decertified, Rodriguez said.
This year, ALADS endorsed Villanueva and spent at least $1.32 million supporting him.
"As far as I'm concerned, Nov. 6 was poetic justice for Alex," Rodriguez said.
Villanueva's abrupt ouster of several top Sheriff's Department officials, leaving no time for the old guard and new administration to overlap and share knowledge, has struck some observers as score-settling.