Jenner, who is separated from Kardashian matriarch Kris Jenner after 22 years of marriage, didn't find out about the ballpark proposal until after the fact.
Jenner and West have "never had a real conversation" a family source said, and Jenner apparently cautioned Kardashian from getting involved with West so shortly after she ended her marriage to Kris Humphries.
Despite the bad blood -- either over the frosty relationship between Jenner and West, or his split from Kris Jenner -- Kardashian still got on the phone with her stepfather immediately after West popped the question.
"Kim considers him to be her father," the source.
West, 36, proposed to Kardashian, 33, at AT&T Park in San Francisco with the help of a 50-piece orchestra and fireworks. West presented Kardashian with an enormous 15-carat diamond ring, and after she said yes, family and friends ran out from the dugout to surprise her.
The newly engaged couple welcomed their daughter, North, in June. The marriage will be the first for West, and the third for Kardashian.