Full sample project: https://github.com/jasonmitchell/aspnetmvc-knockoutjs-quickstart

DynamicModelLoading.cshtml

@using Quickstart.Web.Extensions
@model Quickstart.Web.Models.Person

@section scripts
{
    <script type="text/javascript">
        var viewModel = ko.mapping.fromJS(@Html.Raw(Model.ToJson()));
        ko.applyBindings(viewModel);
    </script>
}

<!-- HTML for view - knockout bindings etc -->

DynamicModelLoading.js

var DynamicModelLoading = function(data) {
    var self = this;
    ko.mapping.fromJS(data, {}, self);

    self.displayFullName = function(model) {
        var fullName = model.firstName() + " " + model.lastName();
        alert(fullName);
    };
};

DynamicModelLoadingWithClientSideFunctions.cshtml

@using Quickstart.Web.Extensions
@model Quickstart.Web.Models.Person

@section scripts
{
    <script type="text/javascript" src="/Scripts/ViewModels/DynamicModelLoading.js"></script>
    <script type="text/javascript">
        var viewModel = new DynamicModelLoading(@Html.Raw(Model.ToJson()));
        ko.applyBindings(viewModel);
    </script>
}

<!-- HTML for view - knockout bindings etc -->

<a href="#" data-bind="click:displayFullName">Display full name</a>