He worked for such Republicans as State Senators John D. Calandra and Guy Velella, Mayors Giuliani and Bloomberg and as the personnel and Labor Relations director and later deputy chief clerk for Bronx County New York City Board of Elections.
Tosi first ran for City Council in 1973 in the 14th district against Anthony J. Mercorella, who was appointed to the seat a few months earlier to fill a vacancy.
Despite a spirited campaign, Tosi, who won about 44 percent of the vote, lost to Democrat Vincent Marchiselli, a pro-life liberal and funeral director who used a wheelchair.
[2] In 1985 and 1989, Tosi ran as the Republican Party's "sacrificial lamb" against popular Democratic Councilman Jerry L. Crispino, who represented the 14th district.
[citation needed] In 1989, Velella asked Tosi to manage the campaign of cosmetics heir Ronald Lauder, who sought the Republican primary for mayor against Rudy Giuliani.
His role in restoring two Bronx school board candidates to the ballot in 1993 despite the fact that there was a question of the required number of signatures came under scrutiny.
Manhattan District Attorney Robert Morgenthau empaneled a grand jury to investigate charges of fraud in the 1993 school board of election.
Tosi resigned as Bronx GOP Chairman as he completed his seminary candidacy and prepared for ordination as a Permanent Deacon in the Roman Catholic Church.
Velella, who had completed his prison term, accused his two former employees, Tosi and Savino, of seizing control of the Bronx GOP illegally.
He was ordained as a Permanent Deacon in the Roman Catholic Church where he served in his ministry until his death on December 4, 2017, aged 81, from congestive heart failure.