diff --git a/internal/cmdutils/bind-viper-to-flags.go b/internal/cmdutils/bind-viper-to-flags.go
index 8f032851..7232e638 100644
--- a/internal/cmdutils/bind-viper-to-flags.go
+++ b/internal/cmdutils/bind-viper-to-flags.go
@@ -17,7 +17,10 @@ limitations under the License.
 package cmdutils
 
 import (
+	"encoding/json"
 	"fmt"
+	"reflect"
+	"strings"
 
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
@@ -31,8 +34,9 @@ func BindViperToFlags(cmd *cobra.Command, viperInstance *viper.Viper) {
 
 		if !flag.Changed && viperInstance.IsSet(configName) {
 			value := viperInstance.Get(configName)
-			err := cmd.Flags().Set(flag.Name, fmt.Sprintf("%v", value))
-			cobra.CheckErr(err)
+			for _, strVal := range viperValueToStrings(value) {
+				cobra.CheckErr(cmd.Flags().Set(flag.Name, strVal))
+			}
 		}
 	})
 
@@ -40,3 +44,32 @@ func BindViperToFlags(cmd *cobra.Command, viperInstance *viper.Viper) {
 		BindViperToFlags(subcmd, viperInstance)
 	}
 }
+
+// viperValueToStrings converts a viper config value to a slice of strings for
+// pflag.Set calls. Slice values (e.g. from YAML lists) produce one string per
+// element. Scalar strings that look like a JSON array (start with "[" and end
+// with "]") are parsed as JSON to support multiple values via env vars, e.g.
+// FGA_CUSTOM_HEADERS='["X-Foo: bar","X-Baz: qux"]'. Other scalars produce a
+// single-element slice.
+func viperValueToStrings(value any) []string {
+	reflectValue := reflect.ValueOf(value)
+
+	if reflectValue.Kind() == reflect.Slice || reflectValue.Kind() == reflect.Array {
+		result := make([]string, 0, reflectValue.Len())
+		for i := range reflectValue.Len() {
+			result = append(result, fmt.Sprintf("%v", reflectValue.Index(i).Interface()))
+		}
+
+		return result
+	}
+
+	str := fmt.Sprintf("%v", value)
+	if strings.HasPrefix(str, "[") && strings.HasSuffix(str, "]") {
+		var parsed []string
+		if err := json.Unmarshal([]byte(str), &parsed); err == nil {
+			return parsed
+		}
+	}
+
+	return []string{str}
+}
diff --git a/internal/cmdutils/bind-viper-to-flags_test.go b/internal/cmdutils/bind-viper-to-flags_test.go
new file mode 100644
index 00000000..42c7123e
--- /dev/null
+++ b/internal/cmdutils/bind-viper-to-flags_test.go
@@ -0,0 +1,98 @@
+/*
+Copyright © 2023 OpenFGA
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package cmdutils
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestViperValueToStrings(t *testing.T) {
+	t.Parallel()
+
+	testcases := []struct {
+		name     string
+		value    any
+		expected []string
+	}{
+		{
+			name:     "scalar string produces single-element slice",
+			value:    "X-Custom-Header: value1",
+			expected: []string{"X-Custom-Header: value1"},
+		},
+		{
+			name:     "typed string slice produces one string per element",
+			value:    []string{"X-Custom-Header: value1", "X-Request-ID: abc123"},
+			expected: []string{"X-Custom-Header: value1", "X-Request-ID: abc123"},
+		},
+		{
+			name:     "any slice produces one string per element",
+			value:    []any{"X-Custom-Header: value1", "X-Request-ID: abc123"},
+			expected: []string{"X-Custom-Header: value1", "X-Request-ID: abc123"},
+		},
+		{
+			name:     "empty slice",
+			value:    []any{},
+			expected: []string{},
+		},
+		{
+			name:     "JSON array string is parsed into multiple entries",
+			value:    `["X-Foo: bar","X-Baz: qux"]`,
+			expected: []string{"X-Foo: bar", "X-Baz: qux"},
+		},
+		{
+			name:     "JSON array with single element",
+			value:    `["X-Foo: bar"]`,
+			expected: []string{"X-Foo: bar"},
+		},
+		{
+			name:     "string starting with [ but not ending with ] is treated as scalar",
+			value:    "[not-an-array",
+			expected: []string{"[not-an-array"},
+		},
+		{
+			name:     "string ending with ] but not starting with [ is treated as scalar",
+			value:    "not-an-array]",
+			expected: []string{"not-an-array]"},
+		},
+		{
+			name:     "invalid JSON array is treated as scalar",
+			value:    "[not valid json]",
+			expected: []string{"[not valid json]"},
+		},
+		{
+			name:     "boolean value is stringified",
+			value:    true,
+			expected: []string{"true"},
+		},
+		{
+			name:     "integer value is stringified",
+			value:    42,
+			expected: []string{"42"},
+		},
+	}
+
+	for _, test := range testcases {
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+
+			result := viperValueToStrings(test.value)
+			assert.Equal(t, test.expected, result)
+		})
+	}
+}