Cochrane, a two-time Olympic medallist, dominated his signature event, the men's 1,500-metre freestyle, winning with a time of 15:06.40 that set a new Pan Am record.
The 26-year-old from Victoria seemed to get stronger as the race went on, beating U.S. swimmer Andrew Gemmell by 3.5 seconds. Brazil's Brandonn Almeida got the bronze.
Cochrane also won the men's 400m freestyle on Friday in Pan Am-record time, and was part of Canada's bronze medal-winning 4x200 freestyle relay team.
Cochrane's gold in the 1,500 free is the first ever by a Canadian at that distance at the Pan Ams.
Pickrem wins bronze
Canada's Sydney Pickrem added her second medal of the Pan Am Games with a bronze in the women's 200m individual medley.
Pickrem, 18, also won a silver medal in the 400 IM.
American swimmers Caitlin Leverenz and Meghan Small won the gold and silver, respectively.
Canada's relay teams add 2 medals
Team Canada closed out the swim competition at the Pan Ams with two medals in the men's and women's 4x100 medley relays.
Canada's women finished with a silver medal, while the men took bronze.- RESULTS: Men's 4x100m medley relay
On the women's side, Dominique Bouchard, Chantal Van Landeghem, Noemie Thomas and Rachel Nicol finished approximately two seconds behind the U.S., which dominated the race from start to finish.
The American team was stacked with the likes of Natalie Coughlin, Allison Schmitt, Kelsi Worrell and Katie Meili, who had a combined eight medals and four golds at this year's Pan Ams entering the relay.
Brazil took the bronze medal.
On the men's side, Canada's team of Santo Condorelli, Richard Funk, Yuri Kisil and Russell Wood finished behind Brazil and the U.S., which won the gold and silver, respectively.
The bronze was Condorelli's fourth medal of the games, Funk's third, and Kisil's second.
Canada's one gold, one silver, and two bronze on Saturday evening gave them eight gold medals and 27 overall for the swimming competition. The U.S. finished with 12 golds and 32 overall, tops in both categories, while the Brazilians collected 26 medals.
Canada's 27 swim medals is a huge improvement on the four they won at the 2011 Pan Am Games.