By 1849, he had arrived in California, briefly prospecting in Grass Valley before finding a job at a drug store in San Francisco.

Despite support for the bill among San Francisco's wealthy, local merchants and the public alike were in staunch opposition.

In a move that stunned many wealthy former supporters, Downey vetoed the Bulkhead Bill, writing: [I]ts provisions are not only in conflict with the constitution and the principles of natural justice, but that the measure as a whole is calculated to work irreparable injury to our commerce, internal and external, of which San Francisco is and must forever remain a metropolis.

Previously part of the Lecompton faction, Downey sided with Anti-Lecomptons, supporting Douglas in his failed bid against Abraham Lincoln.

It meant continued submission and subserviency to slavery and the slave power, which had hitherto dominated the country while the advance of the age had outgrown it ...

It cannot be said that Downey had any special love for slavery or the slave power; on the contrary, he had to a very considerable extent broken loose of the chivalry and what was called an Anti-Lecompton Democrat; but unfortunately for himself, he was still hampered with old-time doctrines when slavery ruled unquestioned ...[4]With the Civil War in its first stages by the 1861 general elections, Downey's earlier support generated by his veto of the Bulkhead Bill had all but evaporated.

When Widney formed a board of trustees, he secured a donation of 308 lots of land from three prominent members of the community: Ozro W. Childs, a Protestant horticulturist; Hellman, a German-Jew; and Downey.

The gift provided land for a campus as well as a source of endowment, the seeds of financial support for the nascent institution.

A porter pulled Downey from the burning wreckage, but his wife's charred body was misidentified and taken to San Francisco for burial.

"Nervous shock" (today called post-traumatic stress disorder) affected Downey for the rest of his life.

In 1888, some time after returning to America, Downey married Rosa V. Kelly, of Los Angeles, who died in 1892.

In 1892 he moved to evict Cupeño American Indians who occupied some of the land as their traditional historic territory, especially near the hot springs (Agua Caliente.)

While the court ruled the Cupeño did have a right to land, it said they had waited too long to press their case, according to a law about the issue when California entered the Union.

Also, during his governorship, the Pony Express began service to San Francisco, and the Central Pacific Railroad was formed.