diff --git a/builder/builder-next/controller.go b/builder/builder-next/controller.go
index 158bf69ef1..17d200d6b7 100644
--- a/builder/builder-next/controller.go
+++ b/builder/builder-next/controller.go
@@ -444,7 +444,7 @@ func newGraphDriverController(ctx context.Context, rt http.RoundTripper, opt Opt
 
 func getGCPolicy(conf config.BuilderConfig, root string) ([]client.PruneInfo, error) {
 	var gcPolicy []client.PruneInfo
-	if conf.GC.Enabled {
+	if conf.GC.IsEnabled() {
 		if conf.GC.Policy == nil {
 			reservedSpace, maxUsedSpace, minFreeSpace, err := parseGCPolicy(config.BuilderGCRule{
 				ReservedSpace: conf.GC.DefaultReservedSpace,
diff --git a/daemon/config/builder.go b/daemon/config/builder.go
index 457f89efc3..22cdd48f4c 100644
--- a/daemon/config/builder.go
+++ b/daemon/config/builder.go
@@ -84,13 +84,17 @@ func (x *BuilderGCFilter) UnmarshalJSON(data []byte) error {
 
 // BuilderGCConfig contains GC config for a buildkit builder
 type BuilderGCConfig struct {
-	Enabled              bool            `json:",omitempty"`
+	Enabled              *bool           `json:",omitempty"`
 	Policy               []BuilderGCRule `json:",omitempty"`
 	DefaultReservedSpace string          `json:",omitempty"`
 	DefaultMaxUsedSpace  string          `json:",omitempty"`
 	DefaultMinFreeSpace  string          `json:",omitempty"`
 }
 
+func (x *BuilderGCConfig) IsEnabled() bool {
+	return x.Enabled == nil || *x.Enabled
+}
+
 func (x *BuilderGCConfig) UnmarshalJSON(data []byte) error {
 	var xx struct {
 		Enabled              bool            `json:",omitempty"`
@@ -103,11 +107,14 @@ func (x *BuilderGCConfig) UnmarshalJSON(data []byte) error {
 		DefaultKeepStorage string `json:",omitempty"`
 	}
 
+	// Set defaults.
+	xx.Enabled = true
+
 	if err := json.Unmarshal(data, &xx); err != nil {
 		return err
 	}
 
-	x.Enabled = xx.Enabled
+	x.Enabled = &xx.Enabled
 	x.Policy = xx.Policy
 	x.DefaultReservedSpace = xx.DefaultReservedSpace
 	x.DefaultMaxUsedSpace = xx.DefaultMaxUsedSpace
diff --git a/daemon/config/builder_test.go b/daemon/config/builder_test.go
index 14b33e8802..3acc463063 100644
--- a/daemon/config/builder_test.go
+++ b/daemon/config/builder_test.go
@@ -28,7 +28,7 @@ func TestBuilderGC(t *testing.T) {
 
 	cfg, err := MergeDaemonConfigurations(&Config{}, nil, configFile)
 	assert.NilError(t, err)
-	assert.Assert(t, cfg.Builder.GC.Enabled)
+	assert.Assert(t, cfg.Builder.GC.IsEnabled())
 	f1 := filters.NewArgs()
 	f1.Add("unused-for", "2200h")
 	f2 := filters.NewArgs()
@@ -61,7 +61,7 @@ func TestBuilderGC_DeprecatedKeepStorage(t *testing.T) {
 
 	cfg, err := MergeDaemonConfigurations(&Config{}, nil, configFile)
 	assert.NilError(t, err)
-	assert.Assert(t, cfg.Builder.GC.Enabled)
+	assert.Assert(t, cfg.Builder.GC.IsEnabled())
 	f1 := filters.NewArgs()
 	f1.Add("unused-for", "2200h")
 	f2 := filters.NewArgs()
@@ -89,3 +89,28 @@ func TestBuilderGCFilterUnmarshal(t *testing.T) {
 	}}
 	assert.DeepEqual(t, cfg.Policy, expectedPolicy, cmp.AllowUnexported(BuilderGCFilter{}))
 }
+
+func TestBuilderGC_Enabled(t *testing.T) {
+	tests := []struct {
+		doc, config string
+		expected    bool
+	}{
+		{doc: "empty config", config: ``, expected: true},
+		{doc: "empty json", config: `{}`, expected: true},
+		{doc: "empty builder", config: `{"builder": {}}`, expected: true},
+		{doc: "empty gc", config: `{"builder": {"gc": {}}}`, expected: true},
+		{doc: "gc enabled", config: `{"builder": {"gc": {"enabled": true}}}`, expected: true},
+		{doc: "gc disabled", config: `{"builder": {"gc": {"enabled": false}}}`, expected: false},
+		{doc: "gc with policy", config: `{"builder": {"gc": {"policy": []}}}`, expected: true},
+	}
+	for _, tc := range tests {
+		t.Run(tc.doc, func(t *testing.T) {
+			tempFile := fs.NewFile(t, "config", fs.WithContent(tc.config))
+			configFile := tempFile.Path()
+
+			cfg, err := MergeDaemonConfigurations(&Config{}, nil, configFile)
+			assert.NilError(t, err)
+			assert.Equal(t, cfg.Builder.GC.IsEnabled(), tc.expected)
+		})
+	}
+}