Bob Alexander is the main villain of the 1993 Comedy-Drama, Dave.

He was played by Frank Langella.

Bob Alexander is The White House Chief of Staff under President William "Bill" Harrison Mitchell. One day, Alexander hires Dave Kovic, the hero of the film, to impersonate the president at a hotel he's speaking at. Dave thinks it's a matter of security, but it's really to cover up Mitchell's extramarital affair with a White House staffer. Mitchell suffers a severe stroke during the rendezvous, leaving him in a coma. Alexander and Communications Director Alan Reed convince Dave to continue impersonating the President. They tell him that Vice President Gary Nance is mentally unbalanced, but in reality, Alexander doesn't want the Vice President in charge because Nance's honesty and good nature would get in the way of his own agenda of lies and Corruption. Alexander, Reed, the secret service, and the medical staff are the only people, who are aware of the switch. First Lady Ellen Mitchell leads a separate life, rarely seeing the President. With the switch of Dave and the president being successful, Alexander sends the vice president on an 12-nation goodwill tour of Africa and frames him for a savings and loans fraud, which Alexander and the president were involved in.

Alexander sets in motion a plan to force the vice president to resign and Dave nominate him as the next president being that the president will die and he was an ex-senator. But when Dave rebuilds the president's popularity by visiting a homeless shelter, Alexander tries to not let any of this happen by forging the president's signature on the veto of a funding bill that will give the homeless shelter homes. When the First Lady talks to Dave about the veto, Dave confronts Alexander himself about it, who arrogantly insults Dave and tells him that if he can cut $650 Million from the federal budget then he can keep the homeless shelter and give them homes. He also warns Dave to never call him again. Alexander becomes even angrier when Dave saves the homeless shelter and admits to Alan that he wanted the shelter closed and that Dave is taking over his job.

The next day, Alexander confronts Dave about calling a press conference saying that it's his job and insults him again. Dave retaliates by blackmailing Alexander into resigning or he will reveal the switch the country. Ellen, who learned about the switch the night before also supports Dave. When Nance returns and confronts Dave about the scandal, Dave talks to Reed, who reveals why Alexander did it. Alexander then tells the country about the president's involvement in the savings and loans crime, which now puts Dave in a bad spot. In a joint session of Congress, Dave admits to Mitchell's role in the scandal, but then he introduces evidence provided by Reed that prove Alexander was the masterminded of the savings and loans crime and that the vice president's involvement was a lie. Alexander sees that Reed had betrayed him and all of his friends and family watching with him leave. After apologizing to Nance and the entire Country, Dave fakes a stroke and makes a switch with the real Mitchell in an ambulance en route to the hospital. Nance becomes Acting President under the terms of the 25th Amendment and is sworn in as President five months later when Mitchell passes away. Alexander and 8 other members of Mitchell's administration are indicted and arrested for 34 charges including the savings and loans crime two days after Dave's jobs initiative passes.